Intravascular fluid catheter with minimal internal fluid volume

ABSTRACT

A catheter-based/intravascular ablation (denervation) system includes a multiplicity of needles which expand open around a central axis to engage the wall of a blood vessel, or the wall of the left atrium, allowing the injection of a cytotoxic or/or neurotoxic solution for ablating conducting tissue, or nerve fibers around the ostium of the pulmonary vein, or circumferentially in or just beyond the outer layer of the renal artery. The expandable needle delivery system is formed with self-expanding materials and include structures, near the end portion of the needles, or using separate guide tubes. The system also includes means to limit and/or adjust the depth of penetration of the ablative fluid into the tissue of the wall of the targeted blood vessel. The preferred embodiment of the catheter delivered through the vascular system of a patient includes a multiplicity of expandable guide tubes that engage the wall of a blood vessel. Injection needles having injection egress at or near their sharpened distal end are then advanced through the guide tubes to penetrate the wall of the blood vessel to a prescribed depth. The ability to provide PeriVascular injection so as to only affect the outer layer(s) of a blood vessel without affecting the media has particular application for PeriVascular Renal Denervation (PVRD) of the sympathetic nerves which lie in the adventitia or outside the adventitia of the renal artery.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 C.F.R. § 1.57.

FIELD OF USE

This invention is in the field of devices to ablate muscle cells andnerve fibers for the treatment of cardiac arrhythmias, hypertension,congestive heart failure and other disorders.

BACKGROUND OF THE INVENTION

Since the 1930s it has been known that injury or ablation of thesympathetic nerves in or near the outer layers of the renal arteries candramatically reduce high blood pressure. As far back as 1952, alcoholhas been used in animal experiments. Specifically Robert M. Berne in“Hemodynamics and Sodium Excretion of Denervated Kidney in Anesthetizedand Unanesthetized Dog” Am J Physiol, October 1952 171:(1) 148-158,describes painting alcohol on the outside of a dog's renal artery toproduce denervation.

At the present time, physicians often treat patients with atrialfibrillation (AF) using radiofrequency (RF) catheter systems to ablateconducting tissue in the wall of the left atrium of the heart around theostium of the pulmonary veins. Similar technology, using radiofrequencyenergy, has been successfully used inside the renal arteries to ablatesympathetic and other nerve fibers that run in the outer wall of therenal arteries, in order to treat high blood pressure. In both casesthese are elaborate and expensive catheter systems that can causethermal, cryoablative, or other methods to injure surrounding tissue.Many of these systems also require significant capital outlays for thereusable equipment that lies outside of the body, including RFgeneration systems and the fluid handling systems for cryoablativecatheters.

Because of the similarities of anatomy, for the purposes of thisdisclosure, the term target wall will refer here to either wall of apulmonary vein near its ostium for AF ablation applications or the wallof the renal artery, for hypertension or congestive heart failure (CHF)applications.

In the case of atrial fibrillation ablation, the ablation of tissuesurrounding multiple pulmonary veins can be technically challenging andvery time consuming. This is particularly so if one uses RF cathetersthat can only ablate one focus at a time. There is also a failure rateusing these types of catheters for atrial fibrillation ablation. Thefailures of the current approaches are related to the challenges increating reproducible circumferential ablation of tissue around theostium (peri-ostial) of a pulmonary vein. There are also significantsafety issues with current technologies related to very long fluoroscopyand procedure times that lead to high levels of radiation exposure toboth the patient and the operator, and may increase stroke risk inatrial fibrillation ablation.

There are also potential risks using the current technologies for RFablation to create sympathetic nerve denervation from inside the renalartery for the treatment of hypertension or congestive heart failure.The short-term complications and the long-term sequelae of applying RFenergy from inside the renal artery to the wall of the artery are notwell defined. This type of energy applied within the renal artery, andwith transmural renal artery injury, may lead to late restenosis,thrombosis, renal artery spasm, embolization of debris into the renalparenchyma, or other problems inside the renal artery. There may also beuneven or incomplete sympathetic nerve ablation, particularly if thereare anatomic anomalies, or atherosclerotic or fibrotic disease insidethe renal artery, such that there is non-homogeneous delivery of RFenergy. This could lead to treatment failures, or the need foradditional and dangerous levels of RF energy to ablate the nerves thatrun along the adventitial plane of the renal artery.

The Ardian system for RF energy delivery also does not allow forefficient circumferential ablation of the renal sympathetic nervefibers. If circumferential RF energy were applied in a ring segment fromwithin the renal artery (energy applied at intimal surface to killnerves in the outer adventitial layer) this could lead to even higherrisks of renal artery stenosis from the circumferential and transmuralthermal injury to the intima, media and adventitia. Finally, the“burning” or the inside of the renal artery using RF ablation can beextremely painful. Thus, there are numerous and substantial limitationsof the current approach using RF-based renal sympathetic denervation.Similar limitations apply to Ultrasound or other energy deliverytechniques.

The Bullfrog® micro infusion catheter described by Seward et al in U.S.Pat. Nos. 6,547,803 and 7,666,163 which uses an inflatable elasticballoon to expand a single needle against the wall of a blood vesselcould be used for the injection of a chemical ablative solution such asalcohol but it would require multiple applications as it does notdescribe or anticipate the circumferential delivery of an ablativesubstance around the entire circumference of the vessel. The most numberof needles shown by Seward is two and the two needle version of theBullfrog® would be hard to miniaturize to fit through a small guidingcatheter to be used in a renal artery. If only one needle is used,controlled and accurate rotation of any device at the end of a catheteris difficult at best and could be risky if the subsequent injections arenot evenly spaced. This device also does not allow for a precise,controlled, and adjustable depth of delivery of a neuroablative agent.This device also may have physical constraints regarding the length ofthe needle that can be used, thus limiting the ability to inject agentsto an adequate depth, particularly in diseased renal arteries withthickened intima. Another limitation of the Bullfrog® is that inflationof a balloon within the renal artery can induce stenosis due to ballooninjury of the intima and media of the artery, as well as causingendothelial cell denudation.

Jacobson and Davis in U.S. Pat. No. 6,302,870 describe a catheter formedication injection into the inside wall of a blood vessel. WhileJacobson includes the concept of multiple needles expanding outward,each with a hilt to limit penetration of the needle into the wall of thevessel, his design depends on rotation of the tube having the needle atits distal end to allow it to get into an outward curving shape. Thehilt design shown of a small disk attached a short distance proximal tothe needle distal end has a fixed diameter which will increase the totaldiameter of the device by at least twice the diameter of the hilt sothat if the hilt is large enough in diameter to stop penetration of theneedle, it will significantly add to the diameter of the device. Foreither the renal denervation or atrial fibrillation application, thelength of the needed catheter would make control of such rotationdifficult. In addition, the hilts which limit penetration are a fixeddistance from the distal end of the needles. There is no built inadjustment on penetration depth which may be important if one wishes toselectively target a specific layer in the blood vessel or if one needsto penetrate all the way through to the volume past the adventitia invessels with different wall thicknesses. Jacobson also does not envisionuse of the injection catheter for denervation. Finally, in FIG. 3 ofJacobson, when he shows a sheath over expandable needles, there is noguide wire and the sheath has an open distal end which makes advancementthrough the vascular system more difficult. Also, the needles, if theywere withdrawn completely inside of the sheath, could, because of thehilts, get stuck inside the sheath and be difficult to push out.

The prior art also does not envision use of anesthetic agents such aslydocaine which if injected first or in or together with an ablativesolution can reduce or eliminate any pain associated with thedenervation procedure.

As early as 1980, alcohol has been shown to be effective in providingrenal denervation in animal models as published by Kline et al in“Functional re-innervation and development of supersensitivity to NEafter renal denervation in rats”, American Physiological Society1980:0363-6110/80/0000-0000801.25, pp. R353-R358. While Kline statesthat “95% alcohol was applied to the vessels to destroy any remainingnerve fibers, using this technique for renal denervation we have foundrenal NE concentration to be over 90% depleted (i.e. <10 mg/g tissue) 4days after the operation” Again in 1983, in the article “Effect of renaldenervation on arterial pressure in rats with aortic nerve transaction”Hypertension, 1983, 5:468-475, Kline again publishes that a 95% alcoholsolution applied during surgery is effective in ablating the nervessurrounding the renal artery in rats. While drug delivery catheters suchas that by Jacobson, designed to inject fluids at multiple points intothe wall of an artery, have existed since the 1990's and alcohol iseffective as a therapeutic element for renal denervation, there is needfor an intravascular injection system specifically designed for thePeriVascular circumferential ablation of sympathetic nerve fibers in theouter layers around the renal arteries with adjustable penetration depthto accommodate variability in renal artery wall thicknesses.

The prior art also does not envision use of anesthetic agents such aslidocaine which, if injected first or in or together with an ablativesolution, can reduce or eliminate any pain associated with thedenervation procedure.

McGuckin, in U.S. Pat. No. 7,087,040, describes a tumor tissue ablationcatheter having three expandable tines for injection of fluid that exita single needle. The tines expand outward to penetrate the tissue. TheMcGuckin device has an open distal end that does not provide protectionfrom inadvertent needle sticks from the sharpened tines. In addition theMcGuckin device depends on the shaped tines to be of sufficient strengththat they can expand outward and penetrate a the tissue. To achieve suchstrength tines would not be small enough so as to have negligible bloodloss when retracted back following fluid injection for a renaldenervation application. There also is no workable penetration limitingmechanism that will reliably set the depth of penetration of theinjection egress from the tines with respect to the inner wall of thevessel, nor is there a pre-set adjustment for such depth. For theapplication of treating liver tumors, the continually adjustable depthof tine penetration makes sense where multiple injections at severaldepths might be needed; however for renal denervation, being able toaccurately dial in the depth is critical so as to not infuse theablative fluid too shallow and kill the media of the renal artery or toodeep and miss the nerves that are just outside or in the outer layer ofthe renal artery.

Finally Fischell et al in U.S. patent application Ser. Nos. 13/092,363,13/092,363 describe expandable intravascular catheters with expandableneedle injectors. In Ser. No. 13/092,363 the Fischells disclose anintravascular catheter with a sheath that, unlike Jacobson, has a closedconfiguration that completely encloses the sharpened needles to protecthealth care workers from needle stick injuries and blood bornepathogens. The Fischell Applications, Ser. Nos. 13/092,363, 13/092,363,however show only designs to operate into the wall of the left atriumaround the ostium of a pulmonary vein or into the wall of the aortaaround the ostium of a renal artery and not from inside a vessel.

SUMMARY OF THE INVENTION

The present invention, Intravascular Nerve Ablation System (INAS), iscapable of applying an ablative fluid to produce circumferential damagein the nerve tissue that is in or near the wall of a blood vessel with arelatively short treatment time using a disposable catheter andrequiring no additional capital equipment. The primary focus of use ofINAS is in the treatment of cardiac arrhythmias, hypertension andcongestive heart failure. Unlike the Bullfrog or RF ablation devicesthat work with one or, at most two, points of ablation, the presentinvention is designed to provide PeriVascular fluid injection allowing amore uniform circumferential injury to the nerves, while minimizinginjury to the intima and medial layers of the vessel wall. The termcircumferential delivery is defined here as at least three points ofsimultaneous injection of a suitable ablative solution within a vesselwall, or circumferential filling of the space outside of the adventitiallayer (outer wall) of a blood vessel. Unlike the Jacobson device of U.S.Pat. No. 6,302,870, which does describe circumferential delivery, thepresent invention does not depend upon rotation of a tube to createoutward movement nor does it have a fixed diameter hilt to limitpenetration. In addition, while Jacobson shows a version of his devicethat pulls back within a sheath like tube, the tube has an open end andthe Jacobson claims require an increase in diameter to accommodate themanifold that allows the fluid flowing in one lumen from the proximalend of the catheter to egress through multiple needles. The preferredembodiment of the present invention uses a manifold that fits within thelumen of the tube thus greatly decreasing the diameter of the catheterwhich enhances delivery of the catheter to the desired site within thehuman body.

Specifically, there is a definite need for such a catheter system thatis capable of highly efficient, and reproducible PeriVascular ablationof the nerves surrounding the renal artery ostium, or distal to theostium in the renal artery wall, in order to damage the sympatheticnerve fibers that track from the peri-ostial aortic wall into the renalarteries, and thus improve the control and treatment of hypertension,etc.

This type of system may also have major advantages over other currenttechnologies by allowing highly efficient, and reproducible PeriVascularcircumferential ablation of the muscle fibers and conductive in the wallof the pulmonary veins near or at their ostium into the left atrium ofthe heart. Such ablation could interrupt atrial fibrillation (AF) andother cardiac arrhythmias. Other potential applications of this approachmay evolve.

The present invention is a small (<2 mm diameter) catheter, whichincludes multiple expandable injector tubes having sharpened injectionneedles their distal ends. The preferred embodiment also includesexpandable guide tubes to guide passage of the coaxial injector tubes tofacilitate penetration of the sharpened injection needles arrangedcircumferentially around the body of the INAS near its distal end.Ablative fluid can be injected through the distal ends of these needleseach having injection egress at or near its distal end. There is apenetration limiting member as part of the INAS so that the needles willonly penetrate into the tissue of the wall of the target blood vessel toa preset distance. These may be a preset distance proximal to the distalend of each needle similar to the hilts of the Jacobson et al patent orthe penetration limiting member may be built into the proximal sectionof the INAS. Limiting penetration is important to reduce the likelihoodof perforation of the vessel wall, optimize the depth of injection or toadjust the depth to be into the PeriVascular volume just outside of theblood vessel wall. In a preferred embodiment for PVRD (PeriVascularRenal Denervation), expandable guide tubes are first deployed againstthe inside wall of the renal artery and act as a guide for separatecoaxially longitudinally moveable injector tubes with sharpenedinjection needles with injection egress port(s) near the distal end.

Ideally, the injection needles should be sufficiently small so thatthere will be no blood loss that following withdrawal after penetrationcompletely through the wall of the renal artery. A major advantage ofthe present invention embodiments is that with such small (<25 gauge)needles, self expanding structures may be quite flimsy and not reliableto ensure accurate penetration of the vessel wall. The present inventionsolves this problem in 2 ways. The use of a cord or wire attached at afixed distance proximal to the distal end of the needles, limitspenetration and connects the expandable injection needles to each otherwill assist in creating uniform expansion of the injection needles tofacilitate reliable penetration of the vessel wall. The preferredembodiment however is the use of expandable guide tubes which open upagainst the inside of the vessel and therefore guide each injectionneedle directly to the point of penetration of the vessel wall. Theguide tubes can be made of a memory metal such as NITINOL or of aplastic material such as polyamide or urethane. The guide tubes shouldalso be radiopaque or have a radiopaque marker at the tip, e.g. atantalum, gold or platinum band. The ideal configuration of the guidetubes is a pre-shaped self-expanding plastic tube with a soft tip so asnot to damage or accidentally penetrate into the wall of the vessel. Thelast 0.5 to 3 mm of this plastic tube could be formed in a filledplastic having a radiopaque material such as barium or tungsten. It isalso envisioned that a two layer plastic tube e.g. urethane on theoutside and polyamide on the inside could provide an even betterstructure. The durometer of the plastic used could also vary with a softmaterial at the tip, a stiffer material in the part that bends andexpands outward and a softer material again in the section proximal tothe expandable section. This last section being softer will facilitatethe delivery of the INAS around the nearly right angle bend through aguiding catheter into a renal artery.

To facilitate the guide tubes staying against the inside wall of thetarget vessel, it is envisioned that the distal portions of the injectortubes including the injection needle would be formed with approximatelythe same radius of curvature as the guide tubes. In reality, the radiusof curvature of the guide tube will vary with the diameter of thevessel, being larger for smaller vessels that will constrain the tubesnot allowing them to completely open up. Thus ideally, the radius ofcurvature of the distal portion of each injector tube including theinjection needle should be the same as the distal portion of the guidetubes at their maximum diameter.

The term expandable will be used throughout this specification todescribe the outward movement of a portion of the present invention withrespect to the longitudinal axis of the INAS catheter. It includes theoutward motion of the guide tubes, injector tubes and/or needles. Thisexpansion can be from the self-expansion of a self-expanding structurethat is released from a constraining structure or it can be expansionfacilitated by distal or proximal motion of another mechanism within theINAS such as a wire that pushes or pulls the expandable structure outfrom the longitudinal axis. Another term that can be used to describe ofthis outward movement is the term deflectable. For example, aself-expanding structure deflects outward when released from itsconstraint and use of a wire moved distally or proximally to cause theoutward movement of the deflectable component would be a manuallydeflectable structure. It is also envisioned that an inflatable ballooncan be used to deflect or expand the deflectable or expandable structureoutward from the longitudinal axis of the INAS.

A preferred embodiment of the present invention that will function invessels of different inside diameters has both the guide tubes andinjection needles at the distal end of the injector tubes having acurved shape. Ideally the expanded shape of the guide tubes will be setso that without constraint of the inside of a vessel, they will achievean expanded diameter slightly larger than the biggest vessel envisionedfor device use. The guide tube shape should also have the distal ends at90 degrees plus or minus 30 degrees to the longitudinal axis of theINAS. For example, the INAS guide tubes could have an unconstraineddiameter of 9 mm where the distal ends curve back 100 degrees, i.e. 10degrees further back than perpendicular to the longitudinal axis of theINAS. Thus when constrained in arteries of 8 mm or less the angles atwhich the guide tubes engage the inside of the vessel will be less than100 degrees. For example, in a 7 mm diameter vessel the distal tips ofthe guide tubes might be close to 90 degrees, in a 6 mm vessel 80degrees, in a 5 mm vessel 70 degrees. Even in a 5 mm vessel, the systemwill still work because of the curved shape of the injection needlesthat will curve back toward the proximal end of the INAS and ensureproper penetration of the vessel wall. It is an important feature of thepresent invention that the injector tubes curve back in the proximaldirection as they extend from the distal end of the guide tubes andpenetrate through the vessel wall. It would be typical for the injectionegress of each injection needle at the distal end of the injector tubesto have a deployed position that is proximal to the distal end of theguide tubes. For example, with the injection egress of the injectionneedles at 2.5 mm distance beyond the distal end of the guide tubes, theinjection egress might be 1 to 2 mm proximal to the distal end of theguide tube.

Because precise depth penetration is preferred, the tubing used for anyof the INAS proximal or distal sections should have limitedstretchability so they do not enlongate during deployment through aguiding catheter into the renal artery. For example, stainless steel,L605 or NINTINOL could be the best material for the proximal sections ofthe INAS. Metal reinforced tubing with reduced elongation tendenciescould be the best for the distal section of the INAS where moreflexibility is needed to go around the nearly right angle bend in theguiding catheter from the aorta to the renal artery.

The penetration limiting function of the present invention INAS asdescribed herein uses one of the following techniques that will greatlyreduce the diameter of the device as compared with the Jacobson designsof U.S. Pat. No. 6,302,870 and thus also improve the ability to deliverit into a vessel of a human body such as the renal artery. Thesetechniques include:

-   -   Use of a cord or wire attached to the multiple needles that can        fold during insertion to limit the diameter of the distal        section of the INAS,    -   Use of one, two or more short NITINOL wires attached in the        longitudinal direction at their proximal ends to the sides of        the needle. The wires being designed to have their distal ends        not be attached and having a memory state that curves away from        the needle so as to act as a penetration limiting member for the        needle. Such wires would fold tight against the needles to        reduce the diameter of the distal section of the INAS,    -   Use of two bends in the needle the bend forming the penetration        limiting member and the bend also being in the circumferential        direction so as to not increase the diameter of the distal        section of the INAS, and    -   The preferred embodiment includes the use of guide tubes that        curve outward through which the needles slide in the        longitudinal direction. The limit for penetration in this design        is integral into the proximal end of the INAS and does not        require diametric volume in the distal section of the INAS. This        last embodiment has the added advantage of allowing adjustment        of the penetration depth. The adjustment could include markings        that allow for precise depth adjustments.

Adjustment of the penetration depth by mechanisms in the proximal end ofthe INAS may be either physician controlled or only accessible duringdevice production. In the first case, use of intravascular ultrasound orother imaging techniques could be used to identify the thickness of therenal artery at the desired site for PVRD. The clinician would thenadjust the depth accordingly. It is also envisioned that the INAS couldbe preset in the factory using the depth adjustment which would not beaccessible to the clinician and if multiple depths are needed, differentproduct codes would be provided. For example, three depths might beavailable such as 2 mm, 2.5 mm and 3 mm. The other advantage of factoryadjustable depth is to simplify calibration and quality production asthe variation for each produced INAS may require a final in factoryadjustment of needle depth so that precise depth of penetration isprovided. It is also an advantage for regulatory filings that a presetdepth or depths be used during trials and for approval to limitpotential error in setting the wrong depth. Finally, it is envisionedthat both an internal adjustment for factory production and calibrationand an externally available adjustment with depth markings could beintegrated into the INAS.

The injector tubes with distal needles are in fluid communication withan injection lumen in the catheter body, which is in fluid communicationwith an injection port at the proximal end of the INAS. Such aninjection port would typically include a standard connector such as aLuer connector used to connect to a source of ablative fluid.

This injection system also anticipates the use of very small gaugeneedles (smaller than 25 gauge) to penetrate the arterial wall, suchthat the needle penetration could be safe, even if targeted to a planeor volume of tissue that is at, or deep to (beyond) the adventitiallayer of the aorta, a pulmonary vein or renal artery. It is alsoanticipated that the distal needle could be a cutting needle or a coringneedle and with a cutting needle the injection egress ports could besmall injection holes (pores) cut into the sides of the injector tubesor distal needle, proximal to the cutting needle tip.

The expandable injector tubes may be self-expanding made of a springymaterial, a memory metal such as NITINOL or they may be made of a metalor plastic and expandable by other mechanical means. For example, theexpandable legs with distal injection needles could be mounted to theoutside of an expandable balloon whose diameter is controllable by thepressure used to inflate the balloon. There should be at least 2injector tubes but 3 to 8 tubes may be more appropriate, depending onthe diameter of the vessel to be treated. For example, in a 5 mmdiameter renal artery, only 3 or 4 needles may be needed while in an 8mm diameter renal one might need 6 needles.

The entire INAS is designed to include a fixed distal guide wire or beadvanced over a guide wire in either an over-the-wire configurationwhere the guide wire lumen runs the entire length of the INAS or a rapidexchange configuration where the guide wire exits the catheter body atleast 10 cm distal to the proximal end of the INAS and runs outside ofthe catheter shaft for its proximal section. The fixed wire version ispreferred as it would have the smallest distal diameter.

The INAS would also include a tubular, thin-walled sheath thatconstrains the self-expanding injection tubes with distal needles and/orguiding tubes prior to deployment, and for removal from the body. Thesheath also allows the distal end of the INAS to be inserted into theproximal end of a guiding catheter or introducer sheath. The sheath alsoserves to protect the operator(s) from possible needle sticks andexposure to blood borne pathogens at the end of the procedure when theINAS is removed from the patient's body.

It is also envisioned that the injection needles, guiding tubes andinjection tubes could be formed from a radiopaque material such astantalum or tungsten or coated, or marked with a radiopaque materialsuch as gold or platinum so as to make them clearly visible usingfluoroscopy.

It is also envisioned that one or more of the injector needles could beelectrically connected to the proximal end of the INAS so as to also actas a diagnostic electrode(s) for evaluation of the electrical activityin the area of the vessel wall.

It is also envisioned that one could attach 2 or more of the expandablelegs to an electrical or RF source to deliver electric current or RFenergy around the circumference of a target vessel to the ostial wall toperform tissue and/or nerve ablation.

It is also envisioned that this device could utilize one, or more thanone neuroablative substances to be injected simultaneously, or in asequence of injections, in order to optimize permanent sympathetic nervedisruption in a segment of the renal artery (neurotmesis). Theanticipated neurotoxic agents that could be utilized includes but is notlimited to ethanol, phenol, glycerol, local anesthetics in relativelyhigh concentration (e.g., lidocaine, or other agents such asbupivicaine, tetracaine, benzocaine, etc.), anti-arrhythmic drugs thathave neurotoxicity, botulinum toxin, digoxin or other cardiacglycosides, guanethidine, heated fluids including heated saline,hypertonic saline, hypotonic fluids, KCl or heated neuroablativesubstances such as those listed above.

It is also envisioned that the ablative substance can be hypertonicfluids such as hypertonic saline (extra salt) or hypotonic fluids suchas distilled water. These will cause permanent damage to the nerves andcould be equally as good or even better than alcohol or specificneurotoxins. These can also be injected hot or cold or room temperature.The use of distilled water, hypotonic saline or hypertonic saline withan injection volume of less than 1 ml eliminates one step in the use ofthe INAS because small volumes of these fluids should not be harmful tothe kidney and so the need to completely flush the ablative fluid fromthe INAS with normal saline to prevent any of the ablative fluid gettinginto the renal artery during catheter withdrawal is no longer needed.This means there would be only one fluid injection step per arteryinstead of two if a more toxic ablative fluid is used.

The present invention also envisions use of anesthetic agents such aslidocaine which if injected first or in or together with an ablativesolution can reduce or eliminate any pain associated with thedenervation procedure.

It is also envisioned that one could utilize imaging techniques such asmultislice CT scan, MM, intravascular ultrasound or optical coherencetomography imaging to get an exact measurement of the thickness andanatomy of the target vessel wall (e.g., renal artery) such that onecould know and set the exact and correct penetration depth for theinjection of the ablative agent prior to the advancement of the injectorneedles or injector tubes. The use of IVUS prior to use of the INAS maybe particularly useful in order to target the exact depth intended forinjection. This exact depth can then be targeted using the adjustabledepth of penetration feature in our preferred embodiment(s). Theselection of penetration depth can be accomplished using the proximalsection/handle or by selection of an appropriate product code for theother designs that might have two to five versions each with a differentpenetration depth limit.

For use in the treatment of hypertension or CHF, via renal sympatheticnerve ablation, the present preferred guide tube embodiment of thisinvention INAS would be used with the following steps:

-   -   1. Sedate the patient in a manner similar to an alcohol septal        ablation, e.g. Versed and narcotic analgesic.    -   2. Engage a first renal artery with a guiding catheter placed        through the femoral or radial artery using standard arterial        access methods.    -   3. After flushing all lumens of the INAS including the injection        lumen with saline, advance the distal end of the INAS with a        fixed distal guidewire into the guiding catheter. Advance the        device through the guiding catheter, until the distal end of the        guiding tubes are at the desired location in the renal artery        beyond the distal end of the guiding catheter.    -   4. Pull back the sheath allowing the expandable guide tubes to        open up until the distal ends of the guide tubes press outward        against the inside wall of the renal artery. This can be        confirmed by visualization of the radiopaque tips of the guide        tubes.    -   5. Next, the radio-opaque injection tubes/needles are advanced        coaxially through the guide tubes to penetrate through the        internal elastic lamina (IEL) at a preset distance (typically        between 0.5 to 4 mm but preferably about 2-3 mm) beyond the IEL        into the vessel wall of the renal artery. Ideally, the very        small gauge injection needles may be advanced to ˜2-3 mm depth        in the renal artery to deliver the neuroablative agent(s) at or        deep to the adventitial plane, in order to minimize intimal and        medial renal artery injury. The correct depth can be determined        prior to the INAS treatment using CT scan, MRI, OCT or        intravascular ultrasound to measure the renal artery wall        thickness, such that the correct initial depth setting for the        injector tube penetration is known prior to advancing the        needles.    -   6. Inject an appropriate volume of the neuroablative fluid, such        as ethanol (ethyl alcohol), distilled water, hypertonic saline,        hypotonic saline, phenol, glycerol, lidocaine, bupivacaine,        tetracaine, benzocaine, guanethidine, botulinum toxin or other        appropriate neurotoxic fluid. This could include a combination        of 2 or more neuroablative fluids or local anesthetic agents        together or in sequence (local anesthetic first to diminish        discomfort, followed by delivery of the ablative agent) and/or        high temperature fluids (or steam), or extremely cold        (cryoablative) fluid into the vessel wall and/or the volume just        outside of the vessel. A typical injection would be 0.1-5 ml.        This should produce a multiplicity of ablation zones (one for        each injector tube/needles) that will intersect to form an        ablative ring around the circumference of the target vessel.        Contrast could be added to the injection either during a test        injection before the neuroablative agent or during the        therapeutic injection to allow x-ray visualization of the        ablation zone.    -   7. Inject normal saline solution into the INAS sufficient to        completely flush the ablative agent out of the injection lumen        (dead space) of the INAS. This prevents any of the ablative        agent from accidentally getting into the renal artery during        pull back of the needles into the INAS. Such accidental        discharge into the renal artery could cause damage to the        kidneys. This step may be avoided if distilled water, hypotonic        or hypertonic saline is used as the ablative fluid.    -   8. Retract the INAS injector tubes/needles back inside the guide        tubes. Then, retract and re-sheath the guide tubes by advancing        the sheath over the guide tubes. This will collapse the guide        tubes back under the sheath completely surrounding the sharpened        needles. The entire INAS can then be pulled back into the        guiding catheter.    -   9. In some cases, one may rotate the INAS 20-90 degrees, or        relocate the INAS 0.2 to 5 cm distal or proximal to the first        injection site and then repeat the injection if needed to make a        second ring or an even more definitive ring of ablation.    -   10. The same methods as per prior steps can be repeated to        ablate tissue in the contralateral renal artery.    -   11. Remove the INAS from the guiding catheter completely.    -   12. Remove all remaining apparatus from the body.    -   13. A similar approach can be used with the INAS, via transeptal        access into the left atrium to treat AF, via ablation of tissue        in the vessel wall of one or more pulmonary veins. When        indicated, advance appropriate diagnostic electrophysiology        catheters to confirm that the ablation (in the case of atrial        fibrillation) has been successful

It is also envisioned that one could mount injector tubes with needleson the outer surface of an expandable balloon on the INAS in order todeliver 2 or more needles into the vessel wall of a target vessel toinject ablative fluid.

Although the main embodiment of this invention utilizes three or moreneedle injection sites to circumferentially administer alcohol or otherneuro-toxic fluid(s) to the wall or deep to the wall of the renal arteryfor sympathetic nerve ablation, it is also envisioned that othermodifications of this concept could also be utilized to achieve the sameresult. In one case it is envisioned that circumferential fluid based(ethanol or other ablative fluid, a combination of ablative fluids, orheated fluid) could be administered in a circumferential fashion to a“ring segment” of the renal artery by injecting the ablative fluid intoa space between two inflated balloons. Thus, after inflating a proximalocclusive balloon and a distal occlusive balloon, the ablative fluidwould be injected into the space between the two balloons and allowed todwell for a short period of time allowing the fluid, such as ethanol topenetrate through the arterial wall and reach the adventitial layer,thus disrupting and ablating the sympathetic nerves running in thisspace. After the dwell period the space could be flushed with saline andthe balloons deflated.

Similarly, a single balloon with a smaller diameter near the middle ofthe balloon could function in the same way, as the ethanol or otherablative fluid, or a combination of ablative fluids, or heated fluid isinjected in the “saddle-like” space in the central part of the balloonthat is not touching the arterial wall.

It is also envisioned that another embodiment may include acircumferential band of polymer, hydrogel or other carrier, on thecentral portion of an inflatable balloon with the carrier containing theneurotoxic agent(s), such as alcohol, phenol, glycerol, lidocaine,bupivacaine, tetracaine, benzocaine, guanethidine, botulinum toxin, etc.The balloon would be inflated at relatively low pressure to oppose theintimal surface of the renal arterial wall, and inflated for a dwelltime to allow penetration of the neurotoxic agent, circumferentially,into a “ring segment” of the renal artery and allow ablation of thesympathetic nerve fibers running near or in the adventitial plane.

It is also envisioned that the INAS catheter could be connected to aheated fluid, or steam, source to deliver high temperature fluids toablate or injure the target tissue or nerves. The heated fluid could benormal saline, hypertonic fluid, hypotonic fluid alcohol, phenol,lidocaine, or some other combination of fluids. Steam injection, ofsaline, hypertonic saline, hypotonic saline, ethanol, or distilled wateror other fluids via the needles could also be performed in order toachieve thermal ablation of target tissue or nerves at and around theneedle injection sites.

It is also envisioned that the INAS could utilize very small diameterneedle injection tubes (e.g., 25-35 gauge) with sharpened needles attheir distal ends such that the needles would be advanced to, or eventhrough the adventitial plane of the renal artery or aortic wall using apenetration limiting member(s) or the combination of the guide tubeswith an adjustable depth advancement of injector tubes through the guidetubes in order to set the depth of penetration, and allow one to “bathe”the adventitial layer containing the sympathetic nerves with neurotoxicfluid, while causing minimal injury to the intimal and medial vesselwall layers. These very tiny needles could pass transmurally through thearterial wall yet create such tiny holes in the arterial wall that bloodleakage from the lumen to outside the vessel as well as medial layerinjury would be minimal, and thus safe. Thus, the present inventioncould have the injection be either into the wall of the renal artery,into the adventitia of the renal artery or deep to the adventitial layer(peri-adventitia) of the renal artery such that the injection needles oregress from injection tubes would occur via penetration all the waythrough the arterial wall to allow the ablative fluid to flow around and“bathe” the outside of the artery with one or more neuroablativesubstances.

Another embodiment may include two or more pores, or small metallic(very short) needle like projections on the outer surface of the centralportion of an inflatable balloon, that would be in fluid communicationwith an injection lumen to allow injection into the wall of the renalartery and allow circumferential delivery of a neurotoxic agent(s).Given these teachings and embodiment descriptions, other similartechniques could be envisioned to allow other variations upon thisconcept of a balloon expandable, circumferential ablation system forrenal artery sympathetic nerve ablation.

The preferred embodiment of the present invention, as described in themethods above, places the means to limit penetration of the vessel wallat the proximal end of the INAS. In this embodiment, at least threeguide tubes with expandable distal portions run along the distal portionof the length of the INAS. A guide tube control mechanism with optionalflushing port is attached to the proximal end of the INAS and controlsthe longitudinal motion of the guide tubes.

One injection tube is included for each guide tube where the injectiontubes have sharpened (coring or cutting needle) distal ends withinjection egress port(s) at or just proximal to the needle tip. Theinjection tubes are located coaxially inside of the guide tubes. Thedistal ends of the sharpened injection needles at the distal ends of theinjection tubes are initially “parked” just proximal to the distal endof the guide tubes. A proximal injector tube control mechanism isattached to the proximal end of the injection tubes, or in the preferredembodiment to the proximal end of a single injector tube that connectsto the multiple injector tubes through a connection manifold. Theinjector tube control mechanism when advanced will advance the injectionneedles out of the distal end of the guide tubes to the desired depth ofpenetration. One example of how the penetration is limited by theproximal section of the INAS is to have the injector tube controlmechanism separated at its distal end from the proximal end of the guidetube control mechanism forming a needle advancement gap. The injectortube control mechanism could have means to adjust the needle advancementgap distance. Alternately, the adjustment could be on the guide tubecontrol mechanism or a separate mechanism between the injector tubehandle and guide tube handle. A fitting for injection of an ablativefluid is attached near the proximal end of the INAS and is in fluidcommunication with the injection lumens of the injector tubes.

In its initial configuration a sheath lies outside of the guide tubesconstraining them. The proximal end of the sheath is attached to asheath handle which can be locked down to prevent longitudinal motionwith respect to the guide tubes or unlocked to allow the sheath to bemoved in the proximal or distal direction to open and close the INAS.

The process to use the INAS proximal section is to have each of thelumens in the INAS flushed with normal saline. The distal end of theINAS is then advanced through a guiding catheter into a vessel such as arenal artery. The sheath control handle is then pulled back holding theguide tube handle in position. This will allow the distal portion of theguide tubes to expand outwardly against the wall of a vessel such as arenal artery. Optionally, after the sheath is pulled back, the guidetubes can then be pushed slightly forward using the guide tube handle toensure they are engaged firmly against the vessel wall. The injectortube handle is then advanced so as to push the distal ends of theinjection tubes having sharpened injection needles out of the distal endof the guide tubes which are touching the inside of the vessel wall. Theneedles will penetrate into the media of the vessel wall. Depending onthe advancement gap, the penetration of the needles into the vessel wallcan be limited. This can permit selective injection through theinjection egress ports of the needles into the media, adventitia,outside of the adventitia (peri-adventitia) or any combination of thesedepending on the number and location of injection egress ports. Afterthe needles are properly placed into or through the vessel wall, asource of ablative fluid such as ethanol is attached to the fitting inthe injection tube handle and the fluid is injected through the lumensinside the injector tubes and out through the injection egress portsinto the tissue.

After the injection is complete, the injection tube handle is pulledback to retract the needles into the distal portion of the guide tubes.The sheath control handle is then advanced to collapse the guide tubesand close the INAS. The sheath control handle is then locked down toprevent inadvertent opening of the INAS. The INAS is then pulled backonto the guiding catheter and the same procedure can be repeated for theother renal artery.

In a preferred embodiment proximal section of the INAS has one handleincluding the sheath control mechanism, the guide tube control mechanismand the injector tube control mechanism. This preferred embodiment hastwo movement sections. A first movement section attached to the sheathcontrol mechanism that moves the sheath with respect to the guide tubes,a second movement section which moves the injector tubes with respect tothe guide tubes. Each of these movement sections would ideally also havea locking mechanism to prevent movement. In addition, it is envisionedthat there would be an interlock between the two movement sections sothat it is impossible to advance the needles unless guide tubes aredeployed and expanded outward and a second interlock that prevents thesheath from closing unless the needles have already been retractedproximally into the guide tubes. The lock/unlock mechanism can be eithera button that is depressed to unlock and released to lock or arotational ring that is twisted in one direction to lock and the otherto unlock.

A preferred embodiment would use the push button mechanism as follows.Push the button on the first movement section that is attached to thesheath control mechanism. This will unlock it from movement with respectto the guide tube control mechanism. Pull this first movement sectionproximally while holding the remainder of the handle fixed. This willpull the sheath in the proximal direction with respect to the guidetubes, allowing the guide tubes to expand outwardly against the insideof the renal artery. Release the button locking the sheath controlmechanism to the guide tube control mechanism in the sheath openposition releasing the interlock that prevents the injector tube controlmechanism from being advanced.

Press the button on the second movement section that is attached to theinjector tube control mechanism unlocking the movement of the injectortube control mechanism with respect to the guide tube control mechanism.Advance the injector tube control mechanism pushing the injector tubeswith sharpened needles out through the distal ends of the guide tubesand into the wall of the vessel. Release the button locking the injectortube control mechanism to the guide tube control mechanism. In thisconfiguration an interlock will prevent the first movement section frombeing able to advance the sheath with respect to the guide tubes whilethe needles are deployed. After injection of the ablative substance andflushing of the INAS with saline, the two steps are reversed. The buttonon the second movement section is now depressed and the injector tubesand needles are retracted proximally into the guide tubes. Releasing thebutton locks the injector tubes control mechanism with respect to theguide tube control mechanism and releases the interlock that preventsthe sheath from closing.

The button on the first movement section can now be depressed and thesheath control mechanism advanced distally with respect to the guidetube control mechanism closing the INAS with the guide tubes nowretracted back under the sheath.

In another embodiment the second movement section is attached to theguide tube control mechanism and the injector tube control mechanism isa third movement section. Here the second movement section only unlocksthe injector tube control mechanism from the guide tube controlmechanism and the injector tube control mechanism is what is pusheddistally to advance the injector tubes with sharpened injection needles.

While a button is described above, a ring that is rotated to lock andunlock the relative movement of the control mechanisms is alsoenvisioned.

Radiopacity of specific portions of the catheter is critical for use ofthe INAS. Ideally, the fixed guide wire at the distal end of the INAS isradio-opaque. There will also be one or more radio-opaque markers at thedistal end of the sheath, on the proximal portion of the distal tip(obturator) of the INAS that closes with the distal end of the sheath,on the end of each guide tube and the distal end or the entire length ofeach injection tube/needle. Metal rings of tungsten, tantalum, gold orplatinum can be used or radiopaque plastics formed with fillings ofdense materials such as barium or tungsten can be used. The injectionneedles can have the needle or needle tip plated with a radiopaque metalor if a coring needle, a sharpened radiopaque plug in the distal end ofthe needle can be used. It is also envisioned that a radio-opaque wirecan be placed inside the injection needle to enhance radiopacity. Forexample a platinum or gold wire of smaller diameter than the needlelumen could fixed inside each needle lumen.

Thus in deploying the INAS, the markers on the sheath and distal tipwill separate showing the retraction of the sheath. The marked ends ofthe guide tubes will then clearly show them separate and touch theinside of the vessel. The injection tubes/needles, when advanced, willbe visible as extending beyond the distal ends of the guide tubes andclearly deep to the lumen of the vessel which can be seen with contrastinjections using the guiding catheter. It is envisioned that fluoroscopyperformed at 90 degrees to the distal portion of the INAS could clearlyshow from center to outside the following markers:

-   -   The radiopaque ring marking the distal end of the sheath    -   Outside of that the radiopaque markers at the ends of the guide        tubes    -   Outside of that the distal portion of the injection needles        extending outward through the vessel wall beyond the distal tip        of each guide tube.

Although it is envisioned that there could be a number from one to 8injector tubes/needles inside of 8 guide tubes, it is likely that 2, 3or 4 tubes is optimal for circumferential tissue ablation.

Another important feature of the present invention INAS is a design thatreduces the internal volume of the INAS the “dead space” to minimize theamount of saline needed to flush the ablative fluid out of the catheterinto the desired volume of tissue. It is anticipated that less than 1 mlof an ablative fluid such as ethanol will be needed to perform PVRD. Thedead space should be less than 1 ml, better yet less than 0.5 ml andideally less than 0.2 ml. With certain design features it is conceivedthat the dead space can be reduced to less than 0.1 ml. Such featuresinclude using a small diameter <0.5 mm ID hypotube for the inner tubeused for fluid injection for the INAS, including a volume occupyingstructure such as a wire placed into the full length of thehypotube/inner tube to reduce the volume of the hypotube and thus theINAS dead space and/or designing the proximal injection port and orinjection manifold at the proximal end of the INAS to have low volume byhaving small <0.5 mm inside diameter and short <2 cm length. Onetechnique envisioned to decrease the dead space inside of the injectionlumens of the INAS is to have a wire inside one or more of the lumens totake up volume.

Although the guide tube embodiment will work well to allow smalldiameter needles to be used that will minimize the potential for bloodloss, other designs are also envisioned including:

-   -   Small diameter injector tubes/needles with a removable stylus        that will provide enhanced radiopacity and/or structural        strength to allow the shaped tube/needle to properly curve        outward and penetrate the vessel wall.    -   A small diameter needle inserted into the distal end of a larger        diameter pre-shaped plastic or metal injector tube

Thus it is an goal of the present invention INAS is to have apercutaneously delivered catheter that can be used to treat atrialfibrillation with one, or more injections of an ablative fluid into thevessel walls of the pulmonary veins near the ostium, or into the leftatrial tissue surrounding one or more of the pulmonary veins.

Another goal of the present invention INAS is to have a percutaneouslydelivered catheter that can be used to treat hypertension with one, ormore injections of an ablative fluid into or deep to, the vessel wall ofthe renal arteries, or into the wall of the aorta surrounding the ostiumof the renal artery.

Another goal of the present invention INAS is to facilitate injection ofan ablative fluid into or beyond the outer layers of the renal artery toreduce or prevent injury to the inner layers including the media of therenal artery.

Another goal of the present invention INAS is to have a design withlimited dead space, less than 0.2 ml and ideally less than 0.1 ml.

Another goal of the present invention is to have a two injection stepmethod for renal denervation where the catheter is filled with normalsaline before insertion into the body, then after needle deployment afirst injection of ablative fluid (for example ethanol) is done followedby a second step to flush all the ablative fluid out of the catheterusing normal saline or a similar fluid that is non-toxic to the kidneys.The INAS is closed and the same two injection steps are used for theother renal artery.

Still another goal of the present invention is to utilize distilledwater, hypertonic or hypotonic fluid as the ablative fluid of choice.This can reduce the injection of ablative fluid to one injection (onestep) per renal artery and shorten the procedure.

Still another goal of the present invention INAS is to have apercutaneously delivered catheter that includes a multiplicity ofcircumferentially expandable injector tubes, each tube having a needleat its distal end with injection egress allowing the delivery of anablative fluid into the wall of a target vessel or into the space beyondthe vessel wall.

Still another goal of the invention is to have a flexible penetrationlimiting member or means attached just proximal to the distal end ofeach injector needle, or relatively blunt tipped guiding tubes to limitthe depth of needle penetration into, or just through, the vessel wall.

Still another goal of the present invention is to have a sheath that inconjunction with a distal tip provide for open and closed positions ofthe INAS. The closed position has the sheath and distal tip touching soas to totally enclose the sharpened needles while the open positionallows the needles to expand outward for injection of the ablative fluidinto or deep to the vessel wall.

Yet another goal of the present invention is to use heated or cooledablative fluid to be the source of the tissue ablation such as withheated or cooled normal saline or to enhance the efficacy of an alreadyablative fluid such as ethanol.

Yet another goal of the present invention INAS is to have one or more ofthe injector needles act as diagnostic electrodes for measurement ofelectrical activity within the wall of the target vessel.

Yet another goal of this invention is to use a multiplicity of coaxiallyguided injector tubes that move slidably within corresponding expandableguiding tubes, to allow the safe, controlled and adjustable depth ofpassage of injector tubes with sharpened needles at their distal endsinto and/or through the wall of a target vessel, to allow controlledchemoablation of nerves in the adventitial or peri-adventitial layer ofan artery while minimizing intimal and medial injury of said artery.

Yet another goal of the present invention is to provide injection of ananesthetic agent before or during injection of the ablative fluid so asto prevent or reduce any pain associated with the denervation procedure.

Yet another goal of the present invention is to include one or more ofthe following radiopaque markers to assist in positioning, opening,closing and using the INAS. These include the following:

-   -   A radiopaque ring marking the distal end of the sheath    -   Radiopaque markers at the ends of the guide tubes either metal        bands or plastic with a radiopaque filler such as barium or        tungsten    -   Radiopaque markers on the distal portion of the injection        needles    -   Radiopaque wires inside the lumen of the injector tubes and/or        injection needles    -   Radiopaque markers or outer layer of a fixed guidewire

These and other goals and advantages of this invention will becomeobvious to a person of ordinary skill in this art upon reading of thedetailed description of this invention including the associateddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross section drawing of the distal portion ofthe present invention Vascular Nerve Ablation System (INAS) having afixed guide wire at its distal end.

FIG. 2 is a schematic view of the distal portion of the INAS in itsclosed position as it would be configured for delivery into the humanbody or to cover the injector needles during removal from the humanbody.

FIG. 3 is a schematic view of the distal portion of the INAS in its openposition as it would be configured for delivery of an ablative solutioninto the target vessel wall.

FIG. 4 is a longitudinal cross sectional drawing of the proximal end ofthe fixed wire embodiment of the INAS of FIGS. 1 through 3 .

FIG. 5A is a schematic view of the distal portion of the closed INAS ofFIG. 2 as it is first advanced out of a guiding catheter into a renalartery.

FIG. 5B is a schematic view of the distal portion of the closed INAS asthe sheath is being pulled back to allow the expandable tubes openagainst the wall of the renal artery distal to the ostium.

FIG. 5C is a schematic view of the distal portion of the fully open INASof FIG. 3 with needles fully embedded into the wall of the renal arteryto allow the infusion of an ablative substance into the vessel wall.

FIG. 5D is a schematic view of the distal portion of the closed INAS asthe distal portion of the INAS is being pulled back into the sheath toclose the INAS either for subsequent use in the other renal artery orfor removal from the body.

FIG. 5E is a schematic view of the distal portion of the closed INAS ofFIG. 2 after it has been closed by retraction of the distal portion ofthe INAS into the sheath either for subsequent use in the other renalartery or for removal from the body.

FIG. 6 is a longitudinal cross section drawing of the embodiment of theINAS that is delivered over a separate guide wire.

FIG. 7 is a longitudinal cross sectional drawing of the proximal end ofan over-the-wire embodiment of the INAS of FIG. 6 .

FIG. 8 is a longitudinal cross section drawing of an injector capable ofdelivering a heated ablative solution into the INAS of FIGS. 1-4 .

FIG. 9 is a longitudinal cross section drawing of the proximal sectionof an injection needle showing longitudinal welded wire penetrationlimiting members.

FIG. 10 is a longitudinal cross section drawing of the proximal sectionof another embodiment of the present invention that delivers an ablativefluid circumferentially to the inside of a target vessel.

FIG. 11 is a longitudinal cross section of another embodiment of thepresent invention INAS in its closed position having four injector tubesthat can slide within four guide tubes. The injector tubes havesharpened needles having injection egress ports at the distal end ofeach injector tubes.

FIG. 12 is an enlargement of the area S12 of FIG. 11 showing the distalportion of the injector tubes and guide tubes.

FIG. 13 is a circumferential cross section at S13-S13 of the INAS ofFIG. 11

FIG. 14 is a longitudinal cross section of the expanded distal portionof the INAS.

FIG. 15 is an enlargement of the area S15 of FIG. 14 .

FIG. 16 is a longitudinal cross section of the proximal end of the INASof FIGS. 11-15 .

FIG. 17 is an enlargement of the area S17 of FIG. 16 .

FIG. 18 is an enlargement of the area S18 of FIG. 16 .

FIG. 19 is a longitudinal cross section of an alternate embodiment ofall but the distal portion of the INAS using multiple guide tubes.

FIG. 20 . is a longitudinal cross section of a central transitionportion connecting the proximal portion of the of the INAS of FIG. 19with the distal portion of the INAS of FIGS. 11-14 .

FIG. 21 is a circumferential cross section at S21-S21 of the INAScentral transition portion of FIG. 20 .

FIG. 22 is a circumferential cross section at S22-S22 of the INAScentral transition portion of FIG. 20 .

FIG. 23 is a circumferential cross section at S23-S23 of the INAScentral transition portion of FIG. 20 .

FIG. 24 is a longitudinal cross section of the proximal end of analternate embodiment of the INAS having coring needles with radiopaquewires in their lumens to provide visualization of the needles whendeployed.

FIG. 25A is longitudinal cross section showing an enlargement of thedistal portion of a guide tube and coring needle of the INAS of FIG. 24.

FIG. 25B is an alternate embodiment of the distal section S25 of theINAS of FIG. 24 with the same structure as FIG. 25A for the injectortubes but with a metal band as a radiopaque marker for the guide tube.

FIG. 26 is a schematic view of an embodiment of the INAS proximalportion having locking mechanisms activated by press-able buttons.

FIG. 27 is a schematic view of the needle section of another embodimentof the present invention INAS having a core wire formed from threetwisted wires and non circular cross section guide tubes.

FIG. 28 is the central portion of a transverse cross section at S28-S28of the INAS of FIG. 27 .

FIG. 29 is a schematic view of a distal portion of yet anotherembodiment of the INAS having a twisted core wire with circular crosssection guide tubes.

FIG. 30 is a schematic view of the inner portion of the INAS thatclearly shows the proximal end of the radiopaque wires that run thelength of the injector tubes to provide radiopacity.

FIG. 31 is the transverse cross section at S31-S31 of FIG. 30 .

FIG. 32A is a schematic view of an embodiment of the INAS distal portionhaving non-circular guide tubes.

FIG. 32B is an end on schematic view showing the guide tubes of FIG. 30A

FIG. 33 is a schematic view of an alternate embodiment of the INAShandle which uses rotation of members to lock and unlock motion betweenthe moving sections.

FIG. 34 is a schematic view of the guide tubes and injection tubes ofanother embodiment of the present invention INAS having three guidetubes that separate from a main guide wire body.

FIG. 35 is a schematic view of yet another embodiment of the presentinvention INAS having injector tubes with distal needles havinginjection egress ports.

FIG. 36A is a longitudinal cross section view of another embodiment ofthe distal portion of an injection needle.

FIG. 36B is a longitudinal cross section view of still anotherembodiment of the distal portion of a plastic injector tube with aninjection needle inserted into its distal end.

FIG. 36C is a longitudinal cross section view of another yet anotherembodiment of the distal portion of a metal injector tube with aninjection needle inserted into its distal end.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross section drawing of the distal portion ofthe present invention Vascular Nerve Ablation System (INAS) 10 having afixed guide wire 25 with tip 28 at its distal end. FIG. 1 shows the INAS10 in its fully open position with the self-expanding injector tubes 15with distal ends sharpened to form injection needles 19 open to theirmaximum diameter. Flexible cords 13 with adhesive 14 that attaches thecords 13 to the injector tubes 15 act as a penetration limiting memberto prevent the distal tip of the needles 19 from penetrating more than amaximum distance L into a vessel wall. The injector tubes can be madefrom any springy material with the preferred material being NITINOL. Aseparate spring or inflatable balloon could be placed inside of theinjector tubes if the tubes are self-expanding to achieve the sameobjective. A balloon while increasing the diameter of the system wouldbe able to push the needles with great force into the vessel wall.

A sheath 12 with radiopaque marker 27 is shown in FIG. 1 in its positionwhere it has been pulled back to allow full expansion of the injectortubes 15. There are 4 injector tubes 15 in this embodiment of the INAS10 although as few as 2 and as many as 12 are envisioned. The distance Lcan be between 0.2 and 2 mm with the optimal being about 1 mm.

The distal section 20 of the INAS 10 includes the distal wire 25,tapered flexible tip 26, radiopaque maker 24 and sheath engagementsection 22 that assures that the distal portion of the INAS 10 willproperly pull back into the sheath 12 following use of the INAS 10 toablate tissue in a vessel of the human body. The INAS 10 is fully closedwhen the two radiopaque markers 27 and 24 are next to each other. Thisprovides a visual indication during fluoroscopy.

The proximal end of the injector tubes 15 are held by a manifold 17 thatis attached inside the distal end of the outer tube 16 and the core wire11. The proximal end of the outer tube 16 is attached to a hypotube 18that continues to the proximal end of the INAS 10. The hypotube 18 istypically made from a metal like 316 Stainless steel and the outer tube16 is made from a plastic or metal reinforced plastic so that it isflexible enough to allow the INAS to easily be advanced and retractedaround the bend in a typical guiding catheter such as that used forangioplasty or stenting of the renal arteries. The outer tube 16 wouldtypically be between 5 and 30 cm long although it is also envisionedthat the INAS 10 could be designed without a hypotube 18 and only aplastic or metal reinforced plastic outer tube 16 running to theproximal end.

The core wire 11 is attached to the inside of the hypotube 18 atjunction point 23. This attachment could for example be by adhesivemeans, welding or brazing. Spot welding is the preferred method. In thisway, the core wire 11 that supports the fixed wire 25 cannot be easilydetached form the INAS 10. The injector lumen 21 inside of the hypotube18 connects to the lumen of the outer tube 16 which is in fluidcommunication with the injector tube lumens 29 of each of the expandabletubes 15 allowing an ablative substance or solution to flow from theproximal end of the INAS 10 through the hypotube 18, through the outertube 16, through the expandable injector tubes 15 and out of thesharpened injector needles 19 into a vessel wall.

FIG. 2 is a schematic view of the distal portion of the INAS 10′ in itsclosed position as it would be configured for delivery into the humanbody or to cover the injection needles 19 during removal from the humanbody. The INAS 10′ includes fixed wire 25 with tip 28, core wire 11,outer tube 16 and sheath 12. In this configuration the two radiopaquemarkers 27 and 24 are adjacent to each other with the sheath 12 beingadvanced to it fully distal position. Of great importance in this designis that in the closed position, the sharpened needles 19 are completelyenclosed by the sheath 12 which is closed over the proximal portion ofthe tapered tip 26.

FIG. 3 is a schematic view of the distal portion of the presentinvention Intravascular Nerve Ablation System (INAS) 10 in its fullyopen position having a fixed guide wire 25 with tip 28 at its distalend. FIG. 3 shows the INAS 10 in its fully open position with theself-expanding injector tubes 15 with distal ends sharpened to forminjection needles 19 open to their maximum diameter. Flexible cords 13with adhesive 14 that attaches the cords 13 to the injector tubes 15 actas a penetration limiting member to prevent the distal tip of theneedles 19 from penetrating more than a maximum distance L shown inFIGS. 1 and 3 into a vessel wall.

A sheath 12 with radiopaque marker 27 is shown in FIG. 3 in its positionwhere it has been pulled back to allow full expansion of the injectortubes 15. There are 4 injector tubes 15 in this embodiment of the INAS.The distal section 20 of the INAS 10 includes the fixed distal wire 25,tapered flexible tip 26, radiopaque maker 24 and sheath engagementsection 22 that assures that the distal portion will properly pull backinto the sheath 12 following use of the INAS 10 to ablate tissue in avessel of the human body. Also shown in FIG. 3 are the outer tube 16with injection lumen 21 and core wire 11.

FIG. 4 is a longitudinal cross sectional drawing of the proximal end ofthe fixed wire embodiment of the INAS 10 of FIGS. 1 through 3 . Thehypotube 18 with injection lumen 21 also shown in FIG. 1 , has a Luerfitting 35 with lumen 36 attached to its proximal end allowing a sourceof an ablative substance of solution to be injected through the lumen 36of the Luer fitting 35 into the lumen 21 of the hypotube 18 andsubsequently out of the injection needles 19 of FIGS. 1 through 3 . Theproximal end of the sheath 12 is attached to the distal end of theTuohy-Borst fitting 30 with handle, 36, inner hub 33 washer 39 andO-Ring 43. As the handle 36 is tightened by screwing it down over theinner hub 33, the O-Ring will compress sealing the Tuohy-Borst fitting30 against the hypotube 18. A side tube 31 with Luer fitting 32 having alumen 34 is designed to allow the lumen 38 between the inside of thesheath 12 and hypotube 18 to be flushed with saline before insertion ofthe INAS 10 into a human body. Before insertion into the body, theTuohy-Borst fitting 30 is tightened onto the hypotube 18 with the sheath12 in its most distal position and the INAS 10′ closed as is shown inFIG. 2 . When in the distal end of the INAS 10′ is properly positionedin one of the renal arteries, the Tuohy-Borst fitting is loosened andthe handle 36 is pulled in the proximal direction while the Luer fitting35 his held in place. This will open the INAS 10 and allow the injectortubes 15 of FIG. 1 to expand outward in the vessel.

FIG. 5A is a schematic view of the distal portion of the closed INAS 10′of FIG. 2 as it is first advanced out of a guiding catheter 80 into arenal artery just distal to the ostium with the aorta. The INAS 10′ isadvanced until the marker band 24 distal to the distal end of theguiding catheter 80. It is anticipated that an optimal distance of 5 to15 mm distal would work best although shorter and longer distances arepossible depending on the geometry of the renal artery and the distanceof penetration of the guiding catheter 80 into the ostium of the renalartery.

FIG. 5B is a schematic view of the distal portion of the closed INAS 10″as the sheath 12 is being pulled back to allow the expandable tubes 15open against the wall of the renal artery just distal to the ostium intothe aorta. In this position, it is desired that the angle A at which thedistal end of the injection needles engage the inside of the vessel wallshould be less than 80 degrees and ideally between 40 and 60 degrees. Ifthe angle is too large, the injection tubes could buckle backwardsinstead of pushing the sharpened needles into the vessel wall. If theangle is too small, the needles might not penetrate properly and mightslide distally along the inside of the vessel wall. After the sheath 12is pulled back so it no longer constrains the expandable injector tubes15, the INAS 10″ is then pushed in the distal direction allowing theinjector tubes 15 to continue their outward expansion as the injectionneedles 19 penetrate into the wall of the renal artery. The penetrationwill stop when the cords 13 engage the wall of the renal artery limitingthe penetration of the needles 19. Alternatively, this “cord” may bereplaced by a nitinol wire structure that is fixably attached to theinjector tubes 15 to provide a (stiffer) metallic penetration limitingmember.

FIG. 5C is a schematic view of the distal portion of the fully open INAS10 of FIG. 3 with needles 19 fully embedded into the wall of the renalartery to allow the infusion of an ablative substance into the vesselwall. Although FIG. 5C show the cords 13 fully expanded, it would betypical for them to be slightly less in diameter than their maximumdiameter when they engage the wall of the renal artery to limit thepenetration of the needles 19. Preferably, the maximum diameter of theINAS 10 system selected for the procedure should be at least 2 to 4 mmgreater than the inside diameter of the renal artery. For example, ifthe renal artery diameter at the desired ablation site is 5 mm indiameter, then a INAS 10 with maximum diameter of 7 to 9 mm should beselected. In the configuration of FIG. 5C, the ablative substance isinjected through the needles 19 into the wall of the renal artery. Thepreferred ablative substance is ethyl alcohol (ethanol), which hashistorically been used to ablate tissue, particularly nerve tissue inthe cardiovascular system. Other agents such as phenol, glycerol, localanesthetic agent(s) such as lidocaine, guenethidine or other cytotoxicand/or neurotoxic agents are also anticipated as possible injectates.

FIG. 5D is a schematic view of the distal portion of the closed INAS itsdistal portion is being pulled back into the sheath 12 to close the INAS10″ either for subsequent use in the other renal artery or for removalfrom the body. A shaded area shows the ablated region 100 where thetissue in the wall of the renal artery has been ablated. If the needledepth of penetration is set at a greater depth (e.g. 2.5-3 mm) theablation zone may be deeper (primarily adventitial) and create lessinjury to the intimal and medial layers of the renal artery wall than isshown in 5D.

FIG. 5E is a schematic view of the distal portion of the closed INAS 10′of FIG. 2 after it has been closed by retraction of the distal portionof the INAS into the sheath 12 either for subsequent use in the otherrenal artery or for removal from the body.

For this embodiment of the INAS 10, the method of use for hypertensionwould be the following steps:

-   -   1. Remove the sterilized INAS 10 from its packaging in a sterile        field, flush the lumen 38 between the outer tube 12 and hypotube        18 with saline.    -   2. Advance the sheath 12 until the INAS 10′ is in its close        position.    -   3. Lock the Tuohy-Borst fitting 30 down onto the hypotube 18 of        FIG. 4 .    -   4. Access the aorta via a femoral artery, typically with the        insertion of an introducer sheath.    -   5. Using a guiding catheter 80 of FIGS. 5A through 5E or a        guiding sheath with a shaped distal end, engage the first        targeted renal artery through the aorta. This can be confirmed        with contrast injections as needed.    -   6. Place the distal end of the INAS 10 in its closed position of        FIG. 2 into the proximal end of the guiding catheter 80. There        is typically a Tuohy-Borst fitting attached to the distal end of        a guiding catheter 80 to constrain blood loss.    -   7. The closed INAS 10 can be pushed through the opened        Tuohy-Borst fitting into the guiding catheter 80.    -   8. Advance the INAS 10 through the guiding catheter, until the        marker band 24 is distal to the distal end of the guiding        catheter within the renal artery as shown in FIG. 5A.    -   9. Pull the sheath 12 back in the proximal direction while        holding the Luer fitting 35 and hypotube 18 the proximal end of        the INAS 10 fixed. This will allow expansion of the injector        tubes 15 against the wall of the renal artery as shown in FIG.        5B.    -   10. Lock the Tuohy-Borst fitting 30 down on the hypotube 18.    -   11. With the Tuohy-Borst fitting at the proximal end of the        guiding catheter 80 loosened advance the sheath 12 and hypotube        18 locked together pushing the sharpened needles 19 into, or        through, the wall of the renal artery as the self-expanding        injector tubes 15 continue to expand outward. The injector tubes        15 will stop penetration when penetration limiting member 13        engages the wall of the renal artery thus limiting the        penetration of the needles 19 to the desired depth.    -   12. Attach a syringe or injection system to the Luer fitting 35        of FIG. 4 that provides ablative fluid that will be injected        into the wall of the renal artery    -   13. Inject an appropriate volume of ethanol (ethyl alcohol) or        other appropriate cytotoxic fluid, or combination of        neuroablative fluids, or heated fluid or steam (e.g., 90-95        degree heated saline solution) from the syringe or injection        system through the lumen 36 and out of the needles 19 into the        wall of the renal artery. A typical injection would be 0.3-5 ml.        This should produce a multiplicity of intersecting volumes of        ablation (one for each needle) that should create a torroid of        ablated tissue around the circumference of the renal artery as        shown as the ablated regions shown in FIGS. 5D and 5E. Contrast        and/or an anesthetic agent such as lidocaine can be injected        before or at the same time as the ablative fluid. Saline can be        used to flush the neuroablative fluid out of the dead space        prior to retraction of the injection tubes/needles.    -   14. Loosen the Tuohy-Borst fitting 30 and while holding the        Tuohy-Borst fitting 30 and sheath 12 fixed, pull the Luer 35        with hypotube 18 in the proximal direction until the expandable        tubes 15 with needles 19 are fully retracted back into the        distal end of the sheath 12 and the marker bands 27 and 25 are        next to one another. This is shown in FIGS. 5D and 5E.    -   15. In some cases, one may advance the INAS 10 again into the        renal artery, rotate it between 20-90 degrees and then repeat        the injection to make an even more definitive volume of        ablation. This would be advantageous if the INAS 10 has fewer        than 4 injector tubes and should not be needed with the 4        injector tubes shown in herein.    -   16. The same methods as per steps 8-15 can be repeated to ablate        tissue around the other renal artery during the same procedure.    -   17. Remove the INAS 10 in its closed position from the guiding        catheter. Being in the closed position, the needles 19 are        enclosed and cannot harm the health care workers, or expose them        to blood borne pathogens.    -   18. Remove all remaining apparatus from the body.

A similar approach can be used with the INAS 10, to treat atrialfibrillation through a guiding catheter inserted through the septum intothe left atrium with the wall of the target vessel being the wall of oneof the pulmonary veins.

FIG. 6 is a longitudinal cross section drawing of the distal portion ofanother embodiment the present invention Vascular Nerve Ablation System(INAS) 40 that is delivered over a separate guide wire 60. FIG. 6 showsthe INAS 40 in its fully open position with the self-expanding injectortubes 45 with distal ends sharpened to form needles 49 open to theirmaximum diameter. Flexible cords 43 connect the injector tube 45 and actas a penetration limiting member to prevent the distal tip of theneedles 49 from penetrating more than a maximum distance D into a vesselwall. Unlike the cord 13 of FIG. 1 , the cords 43 are fed though holes57 in the sides of each injector tube 45 a distance D from the distalend. A drop of adhesive (not shown) can be used to seal the holes andprevent leakage of the ablative substance or solution during injectioninto a vessel wall.

A sheath 42 is shown in its position where it has been pulled back toallow full expansion of the injector tubes 45. There are 4 injectortubes 45 in this embodiment of the INAS 40 although as few as 2 and asmany as 12 are envisioned. The distance D can be between 0.2 and 2 mmwith the optimal being about 0.5-1 mm.

The proximal end of the injector tubes 45 are held by a manifold 47 thatis attached inside the distal end of the outer tube 46 and the innertube 48. An injection lumen 51 lies between the inner tube 48 and outertube 46 proximal to the manifold 47. Ablative material injected throughthe injection lumen 51 will flow into the proximal ends of the injectortubes 45 and then out of the injection needles 49 into one or morelayers of the blood vessel and/or into the volume of tissue just outsidethe vessel wall.

The distal section 50 of the INAS 40 that is coaxially attached to thedistal section of the inner tube 48 includes the tapered flexible tip56, radiopaque maker 55 and sheath engagement section 54 that assuresthat the distal portion of the INAS 40 will properly pull back into thesheath 42 following use of the INAS 40 to ablate tissue in a vessel ofthe human body. The guide wire 60 can be advance and retracted in thelongitudinal direction inside of the guide wire lumen 41 that liesinside of the inner tube 48. The INAS 40 can be configured either as anover-the-wire or a rapid exchange device. If over-the-wire, the guidewire lumen 41 inside of the inner tube 48 runs all the way to theproximal end of the INAS 40 as is shown in FIG. 7 . If a rapid exchangeconfiguration is used then the guide wire would exit from the INAS 40and run external to the outside of the INAS 40 for some portion of thelength of the INAS 40. If a rapid exchange is used then a slot will beneeded in the sheath 42 to allow for the sheath 42 to movelongitudinally with respect to the rest of the INAS 40. The proximal endof the rapid exchange configuration would be identical to that of thefixed wire INAS 10 of FIG. 4 . The guide wire would typically runoutside of the body of the INAS 40 for at least the most proximal 10 cmwith the preferred embodiment having the guide wire exit through theside of the outer tube 46 and sheath 42 between 5 and 15 cm from thedistal end of the INAS 40.

FIG. 7 is a longitudinal cross sectional drawing of the proximal end 70of an over-the-wire embodiment of the INAS 40 of FIG. 6 . The inner tube48 has a Luer fitting 78 attached to its proximal end. The guide wire 60can be advanced through the guide wire lumen 41 inside of the inner tube48. The proximal end of the outer tube 46 is attached to the hub 79 thatis sealed against the inner tube 48, forming the injection lumen 51between the inner tube 48 and outer tube 46. A side tube 74 with lumen76 connects into the hub 79 with a Luer fitting 75 attached to theproximal end of the side tube 74. A syringe or other injection devicecan be attached to the Luer fitting 75 to inject an ablative substanceor solution through the lumen 76 into the injection lumen 51 into theinjector tube 45 of FIG. 6 and out of the ends of the injection needles49 into a vessel wall. The proximal end of the sheath 42 connects to thehub 77 that acts as a handle to slide the sheath 42 coaxially over theouter tube 46 to open and close the INAS 40 of FIG. 6 . A side tube 72with lumen 73 connects into the hub 77. A Luer fitting 71 it attached tothe proximal end of the side tube 72 to allow the lumen 62 between thesheath 42 and the outer tube 46 to be flushed with saline solutionbefore introduction of the INAS 40 in to the human body. While the hub77 shown here is a plastic member, it is envisioned that a Tuohy-Borstfitting such as the Tuohy-Borst fitting 30 of FIG. 4 could be used hereand could be advantageous as it would allow one to lock the sheath 42 inposition onto the outer tube 46 during insertion and removal from thebody so that the distal end of the sheath 42 would remain in its mostdistal position protecting the injection needles 49 and protectinghealth care workers from exposure to needle stick injury.

FIG. 8 is a longitudinal cross section of a disposable injector 90 foruse in providing ablative fluid heated to a preset temperature forinjection through the INAS 10 of FIGs. 1-5C to ablate tissue in a humanbody. The injector 90 includes a syringe 104 with fluid storage volume99 and female Luer fitting 93 that would typically attach to a standardstopcock (not shown) the stopcock being connected to the male Luerfitting 35 at the proximal end of the INAS 10 of FIGS. 1-4 . It is alsoenvisioned that a stopcock could be provided with either the injector 90or INAS 10 or integrated into either. The syringe 104 is surrounded bythe heating coil 94 which is contained within the case 95 filled withheat insulation 96. The power for the heating coil 94 comes from thebattery 98 with positive terminal 91 and negative terminal 92 housed inthe battery case 97. A moveable plunger 101 with handle 102 and distalsealing gasket 103 is used to inject the heated ablative fluid in thevolume 99 through the Luer fitting 93 into the INAS 10 injector lumen 21of FIG. 4 where it will then flow out through the injector needles 19 ofFIGS. 1 and 3 into the tissue as shown in FIG. 5C. The injector 90 mayinclude closed loop electronics with either a display of the temperatureor one or more LEDs that let the user know when the ablative fluid inthe syringe 104 is at the desired temperature. The injector 90 could bemanufactured for a single preset temperature or be adjustable to morethan one temperature. While FIG. 8 shows a manual injection plunger 101,it is also envisioned that a fluid pump or mechanical system to depressthe plunger could be integrated into the injector 90. The use of heatedfluid to abate tissue may be either effective by having a normallybenign substance like normal saline heated to the point where the heatcauses the tissue ablation or the heat may act to improve the ablativeability of a fluid such as alcohol that is normally ablative at room orbody temperature.

FIG. 9 is a longitudinal cross section drawing of the proximal sectionof an injection needle 110 with lumen 111 and distal end 119, showingattached longitudinal memory metal wire penetration limiting members 114and 116 with proximal portions 112 and 113 respectively. These proximalportions 112 and 113 are attached (glued, welded or brazed) to theoutside 115 of the needle so that when the needles 110 are released frominside of the sheath 12 of FIGS. 1-4 the distal portion of the wires 114and 116 will assume their memory state as shown in FIG. 9 forming amember that will limit penetration of the needle tip 119 toapproximately a preset distance L2. Since most arteries have a similarthickness, the distance L2 can be set to ensure the ablative fluidinjected through the needle lumen 111 will emerge in the appropriatevolume of tissue. Selection of the appropriate volume can be set bydifferent values of L2 such that the injection can be set to be in themedia of the artery, the adventitia of the artery or outside theadventitia of the artery. While FIG. 9 shows two wires 114 and 116, onewire would also function to limit penetration or 3 or more wires couldalso be used. Ideally the wire(s) would be attached to the outside ofthe needle 115 on the sides circumferentially of the needle and not onthe inside or outside where the wires 114 and 116 would increase thediameter of the closed INAS 10 of FIGS. 1-4 before the sheath 12 ispulled back to deploy the needles.

It is also envisioned that an injector designed to deliver asuper-cooled ablative fluid into the INAS of FIGS. 1-4 could also beappropriate for this application.

An important aspect of the present invention is the circumferentialdelivery of the ablative fluid with respect to the vessel wall. Suchdelivery from one or more injection egress points must attack the nervetissue circumferentially and at the correct depth to ensure efficacy,and ideally to minimize injury to the healthy and normal cellularstructures of the intimal and medial layers. The circumferentialdelivery can be handled as described above in three different ways.

-   -   1. Injection into the vessel wall at three or more points around        the circumference of the vessel,    -   2. Injection into the space outside of wall of the        vessel—although this can be accomplished by a single        needle/egress point, this is best done with at least two egress        points so that the needles can be kept small so as to allow the        vessel wall to reseal as the needles are retracted.    -   3. Injection into the inside to fill an annular space and        delivery the ablative fluid circumferentially to the inside        surface of the vessel.

FIG. 10 is a schematic view of yet another embodiment of the distalportion of the present invention Intravascular Nerve Ablation System(INAS) 200 in its fully open position having a fixed guide wire 225 withtip 228 at its distal end. FIG. 10 shows the INAS 200 in its fully openposition with the self-expanding injector tubes 215 with distal endssharpened to form injection needles 219 open to their maximum diameter.In this embodiment the injector tubes 215 each have a double bend orkink 214 having length L4 in the circumferential direction. The kinks214 act as a penetration limiting member to prevent the distal tip ofthe needles 219 from penetrating more than a maximum distance L3 into avessel wall.

A sheath 212 with radiopaque marker 227 is shown in FIG. 10 in itsposition where it has been pulled back to allow full expansion of theinjector tubes 215. There are 3 injector tubes 215 in this embodiment ofthe INAS. The distal section 220 of the INAS 200 includes the fixeddistal wire 225, tapered flexible tip 226, radiopaque maker 224 andsheath engagement section 222 that assures that the distal portion willproperly pull back into the sheath 212 following use of the INAS 200 toablate tissue in a vessel of the human body. Also shown in FIG. 10 arethe outer tube 216 with injection lumen 221 and core wire 211. The INAS200 of FIG. 10 would be used in the same way as the INAS 10 of FIGS. 1through 5E with the difference being the use of the kinks (double bends)214 as the penetration limiting members. The kinks 214 being integratedinto the injector tubes 215 as compared with the penetration limiter ofFIGS. 1-5E which are attached to the injector tubes. Adding the kinks214 should be a matter of setting a double bend into the shape of thememory metal (e.g. NITINOL) tubing used to form each of the injectortubes 215 that have sharpened ends that form the injection needles 219.In this embodiment the injector tubes themselves limit the penetrationinto the wall of a target vessel. Processes for shaping and heattreating NITINOL tubing to set the memory are well known.

The present invention has discussed use of the INAS for ablating tissuein the human body. It may also have merit for intravascular injection ofany fluid or medication. The ability to limit the depth of penetrationallows it to inject any fluid selectively into the media, adventitia oroutside of the adventitia of a blood vessel. It is also envisioned thatthe use of the double bend penetration limiting member concept of FIG.10 could be applied to any application where fluid injection is requiredat a preset distance into human tissue.

The term circumferential delivery is defined here as at least threepoints of simultaneous injection spaced circumferentially within avessel wall, or circumferential filling of the space outside of theadventitial layer (outer wall) of a blood vessel.

FIG. 11 is a longitudinal cross section of the another embodiment of thepresent invention INAS 300 in its closed position having four injectortubes 316 that can slide within four guide tubes 315 having expandabledistal portions. The injector tubes 316 with sharpened needles 319 haveinjection egress ports 317 near the distal end of each injector tube316. A sheath 312 with distal radiopaque marker band 327 encloses theguide tubes 315 with coaxial injector tubes 316. The injector tubes 316have injection lumens 321. The distal end of each of the guide tubes 329are tapered to provide a surface that will be approximately parallel tothe vessel wall when the guide tubes 315 expand outward duringdeployment. The distal portion of the guide tubes 315 having a length L5are set in an expanded memory shape and as shown in FIG. 11 areconstrained by the sheath 312 to prevent expansion. The four guide tubes315 are not attached or connected to the core wire 311 over the distanceL5. Proximal to the distance L5 the guide tubes 315 are attached orconnected to the core wire 311 with the preferred embodiment shown inFIG. 13 where the core wire 311 and four guide tubes 315 are embedded ina plastic cylinder 305.

The INAS 300 distal end has a tapered section 326 attached to a distalshapeable fixed guide wire 320 with wire wrap exterior 325, core wire311 and tip 328. The tapered section 326 includes a radiopaque marker324 and proximal taper 323 to facilitate closing the sheath 312 over theproximal section 323 following deployment of the INAS 300 to injectablative fluid into a vessel wall.

FIG. 12 is an enlargement of the area S12 of the INAS 300 of FIG. 11showing guide tubes 315 located coaxially inside of the sheath 312. Thedistal portion of the injector tubes 316 having sharpened needles 319,lumens 321 and injection egress ports 327 are located coaxially insideof the distal portion of the guide tubes 315 with tapered distal ends329. All or a portion of the needles 319 or the entire injector tube(s)may be made of a radiopaque material such as tantalum, platinum or gold.It is also envisioned that the ends of the needles may be coated orplated with a radiopaque material such as gold or that a platinum insertis placed into the distal tip of the injection tube prior to sharpeningthe tip into a cutting needle. Also shown are the core wire 311 and theproximal section 323 of the tapered section 326. It is also envisionedthat a distal portion including the distal end 329 of the guide tubes315 may also be made of, coated or plated with a radiopaque materialsuch as gold.

FIG. 13 is a circumferential cross section at S13-S13 of the INAS 300 ofFIG. 11 clearly showing the four guide tubes 315 attached to the outsideof the core wire 31. The injector tubes 316 with injection lumens 321are located coaxially inside of the guide tubes 315. The injection tubes316 are free to slide in the longitudinal direction within the lumens ofthe guide tubes 315. The injection tubes 316 could also be formed fromnitinol and pre-shaped to parallel the curved distal shape of the guidetubes 315 to enhance the coaxial movement of the injector tubes 316within the guide tubes 315. The guide tubes 315, injection tubes 316 andcore wire 311 lie coaxially within the sheath 312 which is free to slideover these parts. It is also shown how the guide tubes 315 and core wire311 are be embedded in plastic 305 to better hold the parts together orthey could be joined by welding, brazing of use of an adhesive. The useof the plastic 305 also allows a cylindrical surface to which theproximal portion of the sheath 312 can seal to allow flushing of thespace between the inside of the sheath 312 and the outside of theplastic 305 with saline before the start of device use.

FIG. 14 is a longitudinal cross section of the expanded distal portionof the INAS 300′ in the fully open configuration with the injectiontubes 316 shown advanced beyond the distal end of the guide tubes 315.The distal end of the injector tubes 316 has the sharpened needles 319with injection egress ports 317.

In this configuration the sheath 312 has been pulled back to allow theguide tubes 315 to expand outward. The guide tubes 315 are typicallymade from a memory metal such as NITINOL. The injector tube 316 may bemade from any metal such as 316 surgical grade stainless steel or mayalso be made from NITINOL or a radioopaque metal such as tantalum orplatinum. If the elements 315 and 316 are not fabricated from aradio-opaque metal it is envisioned that distal portion of the injectortube(s) 316 and guide tube(s) 315 would be coated with a radio-opaquematerial such as gold, typically at or near the distal end of thetube(s) or a piece of radiopaque material may be used to form or belocated near the sharpened needles 319 at the distal end of the injectortubes. The diameter L6 denotes the memory configuration for the fullyopen guide tubes 315. For use in the renal arteries, L6 would typicallybe between 3 and 10 mm with 8 mm being a best configuration if only onesize is made as very few renal arteries are larger than 7 mm diameter.Also shown in FIG. 14 are the distal ends 329 of the guide tubes 315that in the fully open configuration are parallel to the longitudinalaxis of the INAS 300′. The distal portion of the INAS 300′ has thetapered section 326 attached to the fixed guide wire 320 with tip 328,outer layer 325 and core wire 311.

FIG. 15 is an enlargement of the area S15 of FIG. 14 as it would appearwith the distal end of the injector tube 316 with lumen 321 and distalneedle 319 fully advanced beyond the distal end 329 of the guide tube315. Also shown in FIG. 15 is the arterial wall with internal elasticlamina (IEL), Media, External Elastic Lamina (EEL) and adventitia. FIG.14 shows that the injection egress ports 317 are placed into the heartof the adventitia.

An important feature of the present invention INAS 300 is that thepenetration depth for injection through the injection egress ports isadjustable so that any of the following can be accomplished.

-   -   1. Injection into the media    -   2. Injection into the media and adventitia by positioning one of        the injection egress holes in each.    -   3. Injection into the adventitia as shown in FIG. 15 ,    -   4. Injection into both the adventitia and the volume outside of        the adventitia and    -   5. Injection only into the volume outside the adventitia.

Specifically, the distance L7 that the tip of the needle 319 extendsbeyond the end 329 of the guide tube 315 can be adjusted using theapparatus in the proximal end of the INAS 300

FIG. 16 is a longitudinal cross section of the proximal end of the INAS300 of FIGS. 11-15 . Three handles, the proximal injection handle 330,the central guide tube handle 340 and the distal sheath control handle350 allow the relative longitudinal movement of the sheath 312, guidetubes 315 and injector tubes 316. The position shown for FIG. 16 has thesheath control handle 350 in its most proximal position which wouldindicate the sheath 312 has been fully pulled back in the proximaldirection which would allow the guide tubes 315 to expand outward asshown in FIG. 14 . The gap with distance L8 between the injection handle330 and the guide tube handle 340 can be adjusted using the screwadjustment piece 334 with screw threads 335 that allow it to move withrespect to the proximal portion 333 of the injection handle 330. The gapL8 as set will limit the penetration of the needles 319 and injectionegress ports 317 of the injector tubes 316 into the wall of the targetvessel. Ideally, a scale can be marked on the proximal portion 333 ofthe proximal injection handle 330 so that the medical practitioner canset the gap L8 and thus adjust the penetration distance. A luer fitting338 with access tube 336 is the port for ablative fluid injection intothe handle central lumen 332 which is in fluid communication with thelumens 321 of the injector tubes 316.

The central guide tube handle 340 includes an outer portion 342, asealing member 344 that seals the distal portion of the core wire 311 tothe outer portion 342 and provides four holes through which the fourinjector tubes 316 can slide into the proximal ends of the guide tubes315. A Luer fitting 348 with access tube 346 provides access to thespace between the injector tubes 316 and the guide tubes 315 throughholes in the guide tubes 347.

The distal sheath control handle 350 includes a distal portion 354attached to the outside of the sheath 312 with Luer fitting 358 and sidetube 356 providing access to the lumen under the sheath 312 to allow itto be flushed with saline before the procedure begins. The handle 350also has proximal portion 352 and elastic washer 359 that is compressedby screwing the proximal portion 352 into the distal portion 354 to lockthe position of the sheath 312 with respect to the guide tubes 315.

FIG. 17 is an enlargement of the area S17 of FIG. 16 showing theinjection handle 330 with proximal Luer fitting 338 attached to the sidetube 336 with lumen 331. The proximal portion 333 is sealed against theoutside of the side tube 336 and also seals against the outside of thefour injector tubes 316. This sealing can be by an adhesive or bymolding or forming the proximal piece onto the tubes 336 and 316. Thelumen 331 of the side tube 336 is in fluid communication with thecentral lumen 332 of the proximal portion 333 which is in fluidcommunication with the lumens 321 of the injector tubes 316. Thus anablative fluid injected through the Luer 338 will flow into the lumens321 of the injector tubes 316 and will emerge through the injectionegress ports 317 shown in FIG. 15 into the tissue in or near the wall ofthe target vessel. The screw threads 335 on both the proximal portion333 and screw adjustment piece 334 of the injection handle 330 allowadjustment of the gap L8 of FIG. 16 . The gap L8 as set will limit thepenetration of the needles 319 and injection egress ports 317 of theinjector tubes 316 into the wall of the target vessel. Ideally, a scalecan be marked on the proximal portion 333 of the injection handle 330 sothat the medical practitioner can set the gap L8 and thus adjust thepenetration distance.

FIG. 18 is an enlargement of the area S18 of FIG. 16 showing the centralguide tube handle 340 and the sheath control handle 350.

The central guide tube handle 340 includes an outer portion 342, asealing member 344 that attaches the distal portion of the guide tubes315 and core wire 311 to the outer portion 342. The outer portion 342seals against the plastic 305 in which the guide tubes 315 and core wire311 are embedded. Proximal to the proximal end of the plastic 305, aLuer fitting 348 (shown in FIG. 15 ) with access tube 346 providesaccess to the space between the injector tubes 316 and the guide tubes315 through holes 347 in the guide tubes 315.

The distal sheath control handle 350 includes a distal portion 354attached to the outside of the sheath 312 with Luer fitting 358 (shownin FIG. 15 ) and side tube 356 providing access to the lumen between thesheath 312 and the plastic 305 to allow it to be flushed with salinebefore the procedure begins. The handle 350 also has proximal portion352 and elastic washer 359 that is compressed by screwing the proximalportion 352 into the distal portion 354 to lock the position of thesheath 312 onto the plastic 305. In this locked position with the INAS300 closed as shown in FIG. 11 the INAS 300 is advanced into the bodyuntil the distal end with the marker band 324 of FIG. 11 is in the renalartery. The proximal portion 352 is then loosened so that the sheathcontrol handle 350 can be pulled in the distal direction while holdingthe central guide tube handle 340 fixed. It is envisioned that when theproximal end of the sheath control handle proximal piece 352 touches thedistal end of the outer portion 342 of the guide tube handle 340 asshown in FIG. 18 , that the sheath 312 will be full retracted to allowexpansion of the guide tubes 315 against the wall of the target vessel.

The full procedure for renal denervation using the INAS 300 is asfollows:

-   -   1. Remove the sterilized INAS 300 from its packaging in a        sterile field, flush the injection lumens 321 of the injector        tubes and the space between the sheath 312 and plastic 305 and        injector tubes 316 and guide tubes 315 with saline.    -   2. Access the aorta via a femoral artery, typically with the        insertion of an introducer sheath.    -   3. Using a guiding catheter 80 of FIGS. 5A through 5E or a        guiding sheath with a shaped distal end, engage the first        targeted renal artery through the aorta. This can be confirmed        with contrast injections as needed.    -   4. Place the distal end of the INAS 300 in its closed position        of FIG. 11 into the proximal end of the guiding catheter. There        is typically a Tuohy-Borst fitting attached to the distal end of        a guiding catheter 80 to constrain blood loss.    -   5. The closed INAS 300 is then pushed through the opened        Tuohy-Borst fitting into the guiding catheter.    -   6. Advance the INAS 300 through the guiding catheter, until the        marker band 324 is distal to the distal end of the guiding        catheter within the renal artery.    -   7. Pull the sheath 312 back in the proximal direction while        holding the guide tube handle 340 fixed. This will allow        expansion of the injector tubes 315 against the wall of the        renal artery as shown in FIG. 15 .    -   8. Lock the sheath control handle 350 down on the plastic 305.    -   9. Lock the Tuohy-Borst fitting at the proximal end of the        guiding catheter down onto the sheath 312    -   10. Advance the guide tube handle 340 to be sure the distal ends        329 of the guide tubes 315 are in good contact with the wall of        the renal artery and flaring outward in order to point more        closely to perpendicular to the long axis of the renal artery        wall.    -   11. While holding the guide tube handle 340 fixed, advance the        injection handle 330 until its distal end touches the proximal        end of the guide tube control handle 340. This will cause the        needles 319 to advance through the distal ends 329 of the guide        tubes 315 into the wall of the target vessel to the appropriate        penetration limited by the two handles 330 and 340 touching.    -   12. Attach a syringe or injection system to the Luer fitting 338        that provides ablative fluid that will be injected into the wall        of the renal artery. One could optionally inject an anesthetic        drug like lidocaine and/or contrast media before the ablative        fluid to prevent or reduce the pain associated with the        procedure and/or ensure the needles are in the right position.        It is also conceived that an anesthetic or contrast can be        combined with the ablative fluid.    -   13. Inject an appropriate volume of the ablative fluid from the        syringe or injection system through the lumens 321 of the        injector tubes and out of the injection egress ports 317 into        and/or outside of the wall of the renal artery. A typical        injection would be 1-10 ml. This should produce a multiplicity        of intersecting volumes of ablation (one for each needle) that        should create a torroid of ablated tissue around the        circumference of the renal artery as shown as the ablated        regions shown in FIGS. 5D and 5E.    -   14. While holding the guide tube handle 340 fixed. Pull the        injection handle 330 in the proximal direction retracting the        needles 319 back into the guide tubes 315.    -   15. Unlock the sheath control handle 350 from the plastic 305        and while holding the guide tube control handle 340 fixed,        advance the sheath control handle 350 in the distal direction        until the guide tubes 315 are fully collapsed back into the        distal end of the sheath 312 and the marker bands 327 and 324        are next to one another indicating that the INAS 300 is now in        its closed position as shown in FIG. 11 .    -   16. The same methods as per steps 6-15 can be repeated to ablate        tissue around the other renal artery during the same procedure.    -   17. Remove the INAS 300 in its closed position from the guiding        catheter. Being in the closed position, the needles 319 are        doubly enclosed within the guide tubes 315 which are inside the        sheath 312 so the sharpened needles 319 cannot harm the health        care workers, or expose them to blood borne pathogens.    -   18. Remove all remaining apparatus from the body.

A similar approach can be used with the INAS 300, to treat atrialfibrillation through a guiding catheter inserted through the septum intothe left atrium with the wall of the target vessel being the wall of oneof the pulmonary veins.

FIG. 19 is a longitudinal cross section of the proximal portion of analternate embodiment of the INAS 400 which simplifies the design ascompared to the INAS 300 proximal portion of FIG. 16 . The INAS 400 usesthe identical distal portion design as the INAS 300 of FIGS. 11-15 .Three handles, the proximal injection handle 430, the central guide tubehandle 440 and the distal sheath control handle 450 allow the relativelongitudinal movement of the sheath 312, middle tube 415 and inner tube416 with injection lumen 421. The position shown for FIG. 19 has thesheath control handle 450 near its most proximal position which wouldindicate the sheath 312 has been pulled back in the proximal direction.In this position, as with the INAS 300 of FIGS. 11-18 this will causethe distal portion of the guide tubes 315 to expand outward as shown inFIG. 14 .

The gap with distance L9 between the injection handle 430 and the guidetube handle 440 can be adjusted using the screw adjustment piece 434with screw threads 435 that allow it to move with respect to theproximal portion 433 of the proximal injection handle 430. The proximalend of the screw adjustment piece 434 is the penetration limiting memberthat will limit to the distance L9, the penetration of the needles 319and injection egress ports 317 of the injector tubes 316 into the wallof the target vessel. Ideally, a scale can be marked on the proximalportion 433 of the handle 430 so that the medical practitioner can setthe gap L9 and thus adjust the penetration distance. The central tube416 with lumen 421 is sealed into the proximal piece 433 of the proximalinjection handle 430. A luer fitting 438 with access tube 436 is theport for ablative fluid injection into the handle lumen 432. The lumen439 of the Luer fitting 438 is in fluid communication with the lumen 437of the access tube 436 which is in fluid communication with theinjection lumen 421 of the inner tube 416. The inner tube 416 istypically a metal hypertube although a plastic tube or plastic tube withbraided or helical wire reinforcement is also conceived.

The central guide tube handle 440 attached to and controlling thelongitudinal movement of the middle tube 415 includes a proximal portion444 that can screw into a distal portion 442. When screwed in to thedistal portion 442, the proximal portion 444 will compress the washer445 allowing the handle 440 to be locked down onto the middle tube 415.This is also needed during preparation for use when the Luer fitting 448with side tube 446 can be used to flush the space between the inner tube416 and middle tube 415 with saline solution.

The distal sheath control handle 450 attached to and controlling thelongitudinal movement of the sheath 312 includes a proximal portion 454that can screw into a distal portion 452. When screwed in to the distalportion 452, the proximal portion 454 will compress the washer 455allowing the handle 450 to be locked down onto the sheath 312. This isalso needed during preparation for use when the Luer fitting 458 withside tube 456 can be used to flush the space between the middle tube 415and sheath 312 with saline solution.

FIG. 20 is a longitudinal cross section of a central transition portion460 connecting the proximal portion of the INAS 400 of FIG. 19 with thedistal portion of the INAS 300 of FIGS. 11-15 . The proximal end of thecentral transition portion 460 includes the same three concentric tubeslocated at the distal end of the handle portion of the INAS 400 shown inFIG. 19 . Specifically, the proximal end of the transition portion 460includes the inner tube 416 with injection lumen 421, the middle tube415 and the sheath 312. At the distal end of the inner tube 416, amanifold 410 is inserted which seals the inner tube 416 to the fourinjector tubes 316 such that the lumen 421 of the inner tube 416 is influid communication with the lumens 321 of the four injector tubes 316.In addition, longitudinal motion of the inner tube 416 will therefore betranslated to longitudinal motion of the four injector tubes 316.

The middle tube 415 seals inside of the plastic member 405 which alsoseals to the guide tubes 315 and core wire 311. Longitudinal motion ofthe middle tube 415 will translate into longitudinal motion of the fourguide tubes 315. The sheath 312 is the same sheath as in the distalportions of the INAS 300 of FIGS. 11-15 .

FIG. 21 is a circumferential cross section at S21-S21 of the centraltransition section 460 of FIG. 20 . Looking in the distal direction, onesees in cross section, the three concentric tubes the sheath 312, middletube 415 and inner tube 416. Inside the inner tube one sees the proximalend of the manifold 410 and the proximal ends of the four injector tubes316. It can clearly be seen that the manifold 410 seals the fourinjector tubes 316 into the inner tube 416 and the lumens 321 of theinjector tubes 316 open into the lumen 421 of the inner tube 416.

FIG. 22 is a circumferential cross section at S22-S22 of the centraltransition section 460 of FIG. 20 . Looking in the distal direction onesees in cross section, the sheath 312 and middle tube 415. The middletube 415 is sealed into the distal portion of the plastic member 405.One also sees the proximal end of the four guide tubes 315 and core wire411. It also shows how the four injector tubes 316 enter the proximalends of the guide tubes 315.

FIG. 23 is a circumferential cross section at S23-S23 of the centraltransition section 460 of FIG. 20 . This cross section is identical tothe circumferential cross section shown in FIG. 13 showing the sheath312 and plastic member 405 (was 305 in FIG. 13 ) that seals and attachestogether the four guide tubes 315 and the core wire 311. The injectortubes 316 lie concentrically inside of the four guide tubes 315. Thus,FIGS. 20-23 clearly show how the simplified proximal end of FIG. 19connects to the distal portion of the INAS 300 of FIGS. 11-15 .

FIG. 24 is a longitudinal cross section of the proximal end of analternate embodiment of the INAS 500 having injector tubes 516 withcoring needles 519 with radiopaque wires 518 in their lumens to providevisualization of the needles when deployed. The radiopaque wires 518would typically extend beyond the proximal end of the injector tubes 516where they would be attached to the structure of the INAS 500. While thepreferred configuration has the radiopaque wires 518 simply within thelumen of the injector tubes 516, it is also envisioned that theradiopaque wires could be fixedly attached inside the injector tubesusing adhesive or brazing. If such attachment is used than theradiopaque wires can be shorter then the injection tubes 516 andpositioned in the most distal portion.

In this embodiment the injection egress ports 517 are at the distal endof the coring needles 519. In this configuration the sheath 512 has beenpulled back to allow the guide tubes 515 to expand outward. The guidetubes 515 in this embodiment are made from one or two layers of plasticpreformed in the expanded curved shape. The injector tubes 516 may bemade from any metal such as 316 surgical grade stainless steel, NITINOLor a radiopaque metal such as tantalum or platinum. In this embodimentthe distal portion of each guide tube 516 has a radiopaque section 522that is formed integral to the guide tube and is typically made of aradiopaque plastic such as barium or tungsten filled urethane. Alsoshown in FIG. 24 are the distal ends 529 of the guide tubes 515 that inthe fully open configuration at the diameter L10 are parallel to thelongitudinal axis of the INAS 500. For use in the renal arteries, L10would typically be between 3 and 10 mm with 8 mm being a bestconfiguration if only one size is made as very few renal arteries arelarger than 7 mm diameter.

It is important to have the distal ends 529 of the guide tubes touch asclose as possible to flat against the inside of the renal artery for ifthe angle is too acute then the needles 519 might not properly puncturethe arterial wall. It also turns out that when plastic is used for theguide tubes 515, although formed in a curved shape, the shape can becomesomewhat straightened when pulled back for an extended period of timeinto the sheath. For this reason, it is envisioned that the INAS 500would be packaged in its open configuration so as to reduce the time theguide tubes would be in a straight shape within the sheath.

It is also suggested that the initial shape of the guide tubes 516 wouldhave the ends 529 actually shaped in the fully open position to curveback further than the 90 degrees shown in FIGS. 14 and 24 . For example,if the initial angle was 135 degrees at 8 mm diameter which is theposition for the fully open INAS 500 as formed, then at 7 mm diameterthe angle could be at 120 degrees, at 6 mm-105 degrees, at 5 mm-90degrees, at 4 mm 75 degrees and at 3 mm 60 degrees. Thus the needles 519would engage the vessel wall between 60 and 120 degrees for vesselsbetween 3 and 7 mm in diameter. Thus, in this example, FIG. 24 would bethe shape of the INAS 500 within a 5 mm diameter vessel.

The distal portion of the INAS 500 has the tapered section 526 attachedto the fixed guide wire 520 with tip 528, having an outer layer 525 andcore wire 511. The distal end of the sheath 512 with distal radiopaquemarker 513 is also shown. An enlarged view of section S26 is shown inFIG. 26 .

FIG. 25A is an enlargement of the area S25 of FIG. 24 as it would appearwith the distal end of the injector tube 516 with lumen 521 and distalneedle 519 fully advanced beyond the distal end 529 of the guide tube515. The radiopaque wire 518 is clearly shown within the lumen 521 ofthe injector tube 516. The injector tube 516 would typically be smallerthan a 25 gauge needle and ideally less than 0.015″ in diameter with thelumen 521 being at least 0.008″ in diameter. Thus the radiopaque wire518 must be sufficiently less than the diameter of the lumen 521 so asnot to impede injection but still large enough in diameter to be visibleunder fluoroscopy. Thus an ideal diameter of 0.002″ to 0.006″ shouldwork with a diameter of 0.004″ to 0.005″ being ideal. The preferredoutside and inside diameters for the injector tube 516 would be 0.012″to 0.014″ with the lumen 521 between 0.008″ and 0.010″.

In addition the guide tube 515 is shown with an inner plastic layer 527an outer plastic layer 531 and the radiopaque marker 522. The radiopaquemarker 522 is shown here molded over the inner plastic layer 527 distalto the end of the outer plastic layer 531. The radiopaque marker 522should be at least 0.5 mm long with 1-2 mm being preferred. For example,the inner plastic layer 527 might be Teflon or polyimid, while the outerlayer 531 might be a softer plastic such as urethane or tecothane.Ideally, the distal end 529 of the guide tube 515 would be soft enoughso as to reduce the risk of penetration of the vessel wall when ittouches during deployment. It is also envisioned that a metal band madeof gold, platinum or tantalum could also be used to mark the distal endof the guide tube 515. It is also envisioned that the outer layer 531and the radiopaque marker 522 could be the same so that the entire guidetube 516 would be visible under fluoroscopy.

The use of the radiopaque wires 518 also reduces the dead space withinthe injector tubes 516 as it is important to minimize the amount ofvolume within the entire INAS 500 with the ideal volume being less than0.2 ml. This will facilitate a reduced time injection method for PVRDthat would have the INAS 500 flushed with saline to begin.

One technique envisioned to decrease the dead space inside any of theinjection lumens of the INAS is to have a wire inside the lumen justlike the wire 518 inside of the lumen 521 to take up volume. Similarly,a wire could be inserted into the lumen 421 of the inner tube 416 ofFIG. 20 to take up volume in the lumen 421.

Once in place with the needles through the renal artery wall, the properamount of ablative fluid would be infused. Enough saline would then beinjected to completely flush all of the ablative fluid out of the INAS500. The INAS 500 would be closed and the 2^(nd) renal artery treatedthe same way. The INAS 500 would then be removed from the body. Theradius of curvature R1 of the distal portion of the injector tube 516should be approximately the same as the radius of curvature R2 of theguide tube 515. This will prevent the guide tubes 515 from movingproximally (backing up) as the needles 519 puncture the vessel wall.Thus R1 and R2 should be within 2 mm of each other. It is alsoenvisioned that if the radii of curvature are significantly differentthen the radius of curvature R1 should be less than R2.

In reality the radius of curvature of the distal portion of each guidetube 515 will vary with the diameter of the vessel, being larger forsmaller vessels that will constrain the guide tubes 515 not allowingthem to completely open up. Thus ideally, the radius of curvature of thedistal portion of each injector tube 516 including the injection needle519 should be approximately the same as that of the proximal portion ofthe guide tubes 515 when the guide tubes 515 are expanded to theirmaximum diameter.

The needles 519 extend a distance L11 beyond the distal ends 529 of theguide tubes 515. This distance would typically be between 2 and 4 mmwith the preferred distances being 2.5, 3.0 and 3.5 mm assuming the INAS500 distance L11 is preset in the factory.

FIG. 25B is an alternate embodiment of the distal section S25 of theINAS 500 of FIG. 24 . FIG. 25B has the same structure as FIG. 25A forthe injector tubes 516 with injector needles 519 having injection egress517 and radiopaque wires 518. The difference from FIG. 25A is the meansof radiopaque marker for the guide tube 515. In FIG. 25B, the guide tube515 also has an inner layer 527 and outer layer 531 with distal end 529.The metal radiopaque marker band 505 is attached to the outside of theguide tube 515 close to the distal end 529. The combination of a metalband 505 to show the distal end of the guide tube 515 in with theradiopaque wire 518 to show the extension of the injector tube 516 withinjection needle 519 provide a great combination for visualization thekey portion of the INAS 500 to ensure that the injection egress 517 isproperly situated before the ablative fluid in injected.

FIG. 26 is a schematic view of an embodiment of the proximal section 540(or handle) of the INAS 500 having locking mechanisms activated bypress-able buttons 532 and 542. Specifically, button 532 when depressedunlocks the motion of the sheath control cylinder 535 with respect tothe guide tube control cylinder 533. The sheath control cylinder 535 isattached to the sheath 512 by the transition section 538. The guide tubecontrol cylinder 533 is attached to the middle tube 505 of FIG. 28 thatin turn is connected to the guide tubes 515 of FIGS. 24, 25 and 28 . Thesheath control cylinder 535 includes a notch 531 that is used to limitthe pull back in the proximal distance of the sheath 512.

The button 542 when depressed, unlocks the motion of the needle controlcylinder 545 with respect to the guide tube control cylinder 533.

The handle 540 has two flushing ports. Port 534 which would typicallyhave a Luer fitting is shown with a cap 536. Port 534 is used to flushwith saline the space 507 shown in FIG. 28 between the sheath 512 andthe middle tube 505 as well as the space between the sheath 512 and theguide tubes 515. Port 544 which would typically have a Luer fitting isshown with cap 546. Port 544 is used to flush with saline the space 508between the middle tube 505 and the inner tube 506. The injection port554 which typically has a Luer fitting is shown with cap 556. Port 554allows injection of the ablative fluid into the lumen 521 of FIG. 28which is in fluid communication with the lumens of the injector tubes516.

The handle 540 also includes a gap adjustment cylinder 548 that whenrotated in one direction reduces the distance the injection needles 519extend beyond the end of the guide tubes 515. Rotation in the otherdirection of the cylinder 548 will increase the distance the injectionneedles 519 extend beyond the distal ends 529 of the guide tubes 515. Itis envisioned that the gap adjustment cylinder could be accessible tothe user of the INAS 500 with markings on the handle 540 to indicate thedistance that will be achieved. In a preferred embodiment the gapadjustment cylinder 548 could be accessible only during assembly andtesting of the INAS 500 to ensure a properly calibrated distance L11 ofFIG. 25 is preset in the factory during manufacturing and testing ofeach INAS 500. This ability to calibrate the distance L11 is critical toa good yield during manufacturing. In other words, even with variationof a few millimeters in the relative lengths of the components of theINAS 500 such as the inner tube 506 and middle tube 505, the distanceL11 can be dialed in exactly using the gap adjustment cylinder 548. Inthis preferred embodiment, the INAS 500 would be labeled according tothe preset distance L11 shown in FIG. 25 . For example, the INAS 500might be configured to have three different distances L11 of 2.5 mm, 3mm and 3.5 mm. It is also envisioned that a set screw or other mechanismnot shown could be included to lock the gap adjustment cylinder 548 atthe desired distance setting after calibration. While a gap adjustmentcylinder 548 is shown here, it is envisioned that other mechanisms suchas a sliding cylinder could also be used to adjust the distance L11.

The function of the handle 540 to operate the INAS 500 for PVRD wouldinclude the following steps:

-   -   1. Flush all of the internal volumes of the INAS 500 with normal        saline through the ports 534, 544 and 554.    -   2. Insert the INAS 500 through a previously placed guiding        catheter positioning the distal portion of the INAS 500 at the        desired location in one renal artery of the patient.    -   3. Depress the button 532 and while holding the needle control        cylinder 545 which is locked to the guide tube control cylinder        533, pull the sheath control cylinder 535 in the proximal        direction until the notch 531 engages the port 544 limiting the        pull back of the sheath 512.    -   4. Release the button 532 which relocks the relative motion of        the sheath control cylinder 535 with respect to the guide tube        control cylinder 533.    -   5. Depress the button 542 that release relative motion of the        injection needle control cylinder 545 with respect to the guide        tube control cylinder 533 and while holding the sheath control        cylinder 535 which is now locked to the guide tube control        cylinder 533, advance the needle control cylinder 545 with        distal end 549 until the penetration limiting mechanism stops        the motion and the preset depth L11 of the needles 519 with        respect to the distal ends 529 of the guide tubes 515. There are        two ways this can be done: 1) The distal end 549 of the needle        control cylinder 545 is pushed forward until it engages the        guide tube flush port 544 or 2) the internal gap 547 is closed        against the proximal end of the gap adjustment cylinder 548        inside the needle control cylinder 545 as shown in FIG. 26 .    -   6. Release the button 542 which relocks the motion of the        injection needle control cylinder 545 to the guide tube control        cylinder 533.    -   7. In this position a syringe or manifold with syringes (not        shown) can be attached to the port 554 and the desired volume of        ablative fluid is injected. For example 0.2 ml of ethanol could        be injected. If it is desired to verify the position of the INAS        500 needles 519, angiography can be performed looking down the        length of the renal artery such that concentrically one would        see the radiopaque rings 513 and 524 on the distal end of the        sheath 512 and tapered distal end 520, outside of that the        radiopaque markings on the guide tubes 522 and extending into        the wall of the renal artery and into the peri-vascular space,        the distal portion of the injector tubes 516 with internal        radiopaque wires 518. This can be done with or without contrast        injection into the renal artery    -   8. Next a syringe with normal saline solution is attached to the        port 554 replacing the ablative fluid syringe. Ideally, slightly        more saline is injected than the total volume of dead space to        ensure there is no ablative fluid left in the INAS 500. For        example, if the dead space in the INAS 500 is 0.1 ml then 0.12        to 0.15 ml of saline would be a good amount to ensure the        ablative fluid is all delivered to the appropriate peri-vascular        volume of tissue.    -   9. Depress the button 542 and while holding the sheath control        cylinder 535, pull the needle control cylinder 545 back in the        proximal direction until the injection needles 519 are fully        retracted back inside the guide tubes 515. It is envisioned that        a click or stop would occur when the injection needle control        cylinder 545 reaches the correct position so that the injection        needles 519 are fully retracted.    -   10. Release the button 542 locking the motion of the injection        needle control cylinder 545 to the guide tube control cylinder        533.    -   11. Depress the button 532 releasing the relative motion of the        sheath control cylinder 535 with respect to the guide tube        control cylinder 533 that is now locked to the injection needle        control cylinder 545.    -   12. Advance the sheath control cylinder 535 in the distal        direction while holding the injection needle control cylinder        545 fixed. This will close the INAS 500, collapsing the guide        tubes 515 back inside the sheath 512.    -   13. Pull the INAS 500 back into the guiding catheter.    -   14. Move the guiding catheter to the other renal artery.    -   15. Repeat steps 3 through 13 for the other renal artery    -   16. Remove the INAS 500 from the body.

While the buttons 532 and 542, as described above, release the motion ofcontrol cylinders when depressed and lock when released, it is alsoenvisioned that they could also be interlocked as follows:

-   -   1. The first interlock allows the injection needle control        cylinder 545 to be unlocked only when the sheath control        cylinder 535 is in its most distal position where the sheath 512        is pulled back and the guide tubes 515 are fully deployed.    -   2. The second interlock allows the sheath control cylinder 535        to be unlocked only when the injection needle control cylinder        545 is in its most distal position where the needles 519 are        retracted within the guide tubes 515.

The combination of the buttons 532 and 542 with the control mechanismsdescribed above should make the use of the INAS 500 simple andfoolproof. One basically presses button 532 and pulls the sheath 512back releasing the guide tubes 515 to expand outward, then press button542 and advance the needles 519 forward to penetrate the wall of therenal artery. Injections are performed then the reverse is done withbutton 542 depressed and the needles 519 retracted, then button 532depressed and the sheath 512 pushed forward collapsing the guide tubes515 and closing the INAS 500.

FIG. 27 is a schematic view of the needle section of another embodimentof the present invention INAS 550 having a core wire 561 formed fromthree twisted wires 561A, 561B and 561C and non circular cross sectionguide tubes 565 having radiopaque distal section 572 and distal ends579. The INAS 550 is somewhat similar to the INAS 500 of FIG. 24 . Ithas a sheath 512 with distal radiopaque marker 513, injector tubes 566with distal injection needles 569 and injection egress ports 567. Thetapered distal section 580 has a tapered section 576, a radiopaquemarker 574 and a proximal section 573. Of significant importance in thisembodiment is the backward curved shape of the injector tubes 566 withinjection needles 569. Specifically, the radius of curvature of theinjector tubes 566 should match or be slightly smaller (more curvedthan) the radius of curvature of the guide tubes 565 and the guide tubedistal radiopaque sections 572. This will prevent straightening of theguide tubes 565 including the distal radiopaque sections 572 as theneedles 569 penetrate the wall of the target vessel. FIG. 27 shows thefully deployed shape of the INAS 550 where the center of the injectionegress ports 567 are proximal by a distance L12 from the center of thedistal ends 579 of the guide tubes 565 with radiopaque section 572. L12should be between 0.5 mm and 5 mm.

FIG. 28 is the central portion of a transverse cross section at S28-S28of the INAS 550 with sheath 512 of FIG. 27 . It shows the non circularcross section guide tube 565 surrounding the injector tubes 566. At theposition S28-S28, the middle tube 564 which is connected to the guidetube control cylinder 533 of FIG. 26 , is fixedly attached to theoutsides of the three guide tubes 565 as well as the three wires, 561A,561B and 561C which twist together to become the core wire 561 as shownin FIG. 27 . This can be accomplished by injecting plastic or adhesiveto form the connective media 555 within the lumen of the middle tube564.

FIG. 29 is a schematic view of a distal portion of yet anotherembodiment of the INAS 600 having a twisted core wire 611 with circularcross section guide tubes 615 having distal radiopaque sections 622.

With the exception of the twisted core wire 611 and three rather than 4injection needles, the INAS 600 is somewhat similar to the INAS 500 ofFIG. 24 . It has a sheath 612 with distal radiopaque marker 613,injector tubes 616 with distal injection needles 619 and injectionegress ports 617. It also has the radiopaque wires 618 that lie withinthe injector tubes 616 to assist in visualization during fluoroscopy.The tapered distal section 620 has a tapered section 626, a radiopaquemarker 624 and a proximal section 623. Similar to the INAS 550 of FIGS.27 and 28 , this embodiment has a backward (proximal) curved shape ofthe injector tubes 616 with injection needles 619. Specifically, theradius of curvature of the injector tubes 616 should match or beslightly smaller (more curved than) the radius of curvature of the guidetubes 615 and the guide tube distal radiopaque sections 622. This willprevent straightening of the guide tubes 615 including the distalradiopaque sections 622 as the needles 569 penetrate the wall of thetarget vessel.

For better visualization, in FIG. 29 , the proximal portion of thesheath 612 and middle tube 614 are shown as transparent so the internalstructure of the INAS 600 is evident. Specifically, the three circularcross section guide tubes 615 would be connected to the middle tube 614using a technique similar to the INAS 550 of FIG. 28 . Also shown is thewire 611A which is one of the three wires that twist together to formthe core wire 611 also as shown in FIGS. 27 and 28 . The inner tube 606which connects to the needle control cylinder 545 of FIG. 26 , isinternally attached to the three injector tubes 616 using a manifold(not shown) similar to that of the manifold 410 of FIG. 20 . The threeinjector tubes 616 are shown as they enter the proximal end 605 of thethree guide tubes 615.

FIG. 30 is a schematic view of the inner portion of the INAS 600 thatclearly shows the proximal end of the radiopaque wires 618 that run thelength of the injector tubes 616 to provide radiopacity. Theseradiopaque wires 618 are similar to the radiopaque wires 518 of FIGS. 24and 25 . Clearly visible in this inner portion which has the sheath 612and middle tube 614 removed, is the inner tube 606 which is transparent,the 3 guide tubes 615, the three injector tubes 616, 611A and 611B whichare two of the component wires of the core wire 611 of FIG. 29 . Themanifold 610 is shown in FIG. 30 as being inside the inner tube 606. Thedistal portion of the manifold 610 is shown with the proximal portionbeing transparent. Although not shown, the proximal transparent portionof the manifold 610 extends all the way to the proximal end of theinjector tubes 616 similar to the manifold 410 of FIG. 20 . Finally, theradiopaque wires 618 which exit the proximal end of the injector tubes616 are folded back and run back in the distal longitudinal direction inthe space beside the injector tubes 616.

As shown in FIG. 31 which is the transverse cross section at S31-S31 ofFIG. 30 , the manifold 610 that is either molded or injected plastic oradhesive, seals together the inside of the inner tube 606 with the threeinjector tubes 616 and three radiopaque wires 618. In the full catheter600 not just the inner portion

FIG. 32A is a schematic view of an embodiment of the INAS 700 distalportion having non-circular guide tubes 715. Also shown is the core wire711 and tapered with an elliptical or oval cross section. The tapereddistal section 720 has a tapered section 726, a radiopaque marker 724and a proximal section 723. The distal end of the sheath 712 is justvisible. The guide tubes 715 in this embodiment can be made of NITINOLor a formed plastic such as polyamid. The advantage of the non-circularcross section of the guide tubes 715 is to provide better support forthe injector tubes (not shown) as they are pushed distally to engage theinside wall of the target vessel.

FIG. 32B is an end on schematic view of the INAS 700 of FIG. 32A lookingin the proximal direction, just proximal to the proximal end of thetapered distal section 720. Here you can see that rather than the guidetubes 715 being oriented to expand outward in a purely radial direction,the guide tubes 715 are rotated 90 degrees to the radial direction toallow the non-circular cross section to have a reduces impact oncatheter diameter. The core wire 711 is seen in cross section as well asthe distal end of the sheath 712.

FIG. 33 is a schematic view of an embodiment of the proximalsection/handle 640 of the INAS 600 having locking mechanisms activatedby rotation of the sheath control lock 632 and the needle control lock642. Specifically rotation of the sheath control lock 632 counter clockwise form the position shown in FIG. 33 until the sheath flush tube 636with Luer port 634 lines up with the longitudinal slot 631 will unlockthe motion of the sheath control cylinder 635 which is attached to thesheath 612 through the tapered section 638. The sheath control cylinder635 and tapered section 638 can now be pulled in the proximal directionwith respect to the guide tube control cylinder 633 to retract thesheath with respect to the guide tubes as seen in the configuration ofFIG. 29 . Once the sheath control cylinder 635 is pulled all the wayback in the proximal direction, the sheath flush tube 632 will now lineup with the circumferential slot 633 which extends in the clockwisedirection within the sheath control lock 632. In this position, thesheath control lock can be rotated further in the counter clockwisedirection so that the sheath flush tube 636 lies within thecircumferential slot 633 and prevents longitudinal motion of the sheathcontrol cylinder 635. It is envisioned that springs could be embedded inthis mechanism so that once the sheath flush tube 636 is lined up withthe slot 633, the sheath control lock 632 would automatically spring tothe locked position.

Once the sheath 612 has been retracted in the proximal direction asdescribed above, the handle is ready to have the injector tubes 616 withinjection needles 619 of FIG. 29 advanced distally to penetrate thevessel wall of the target vessel. The circumferential slots 643 and 648are connected by the longitudinal slot 641. A locking pin 647 attachedto the outside of the needle control cylinder 645 tracks within thethree slots 643, 641 and 648 to lock and unlock the relative motion ofthe guide tube control cylinder 633 with respect to the needle controlcylinder 645. To enable advancement of the injector tubes 616 of FIG. 29, the needle lock cylinder 642 is rotated in the clockwise direction toalign the pin 647 with the longitudinal slot 641. The needle controlcylinder 645 can now be moved in the distal direction causing theinjector tubes 616 to advance distally. When the pin 647 now reaches aposition aligned with the circumferential slot 648, it can no longermove any more in the distal direction and the penetration of the needles619 is therefore limited. In this configuration, additional clockwiserotation of the needle lock cylinder 642 will move the pin 647 into thecircumferential slot 648 which will now lock longitudinal motion of theneedle control cylinder 645. A syringe can now be attached to the Luerfitting 654 and appropriate ablative fluid injected into theperi-vascular space as desired. An additional injection of saline orother inert fluid to flush the internal dead space of the INAS 600 andensure full delivery of all the ablative fluid to the desired site wouldnow be done. The reverse of the sheath 612 retraction and injector tube616 distal motion can now be accomplished by the reverse motion of thecomponents of the handle 640.

It is also envisioned that the proximal section 640 can be built suchthat the reverse direction of rotation of any of the steps above wouldwork. Also the combination of rotational motion such as described forthe proximal section/handle 640 of FIG. 33 with a button lock/unlockmechanism such as is shown in the proximal section/handle 540 is clearlyenvisioned here.

FIG. 34 is a schematic view of the guide tubes 815 and injection tubes816 of another embodiment of the present invention INAS 800 having threeguide tubes 815 that separate from a main guide wire body 813. Eachguide tube 815 has two lumens, on for passage of the injector tubes 816and the other for a wire 818 which provides the shape memory that causesthe guide tubes 815 to open up against the inside vessel wall of thetarget vessel The wire 818 can also provide additional radiopacity forvisualization of the guide tubes 815. The guide tubes 815 and guide tubebody 813 in the INAS 800 would be made from a plastic material, softenough to allow the wire 818 to cause the guide tubes 815 to form theshape shown. It is also envisioned that the guide tubes 815 themselveswould include a radiopaque material such as Tungsten or Barium. Thewires 818 could be made from a shape memory alloy such as NITNOL or froma pre-shaped spring material such as spring steel. Also show is theproximal end of the inner tube 806 which attaches to the injector tubes816 with distal ends having sharpened injection needles 819 withinjection egress 817.

FIG. 35 is a schematic view of yet another embodiment of the presentinvention INAS 900 having injector tubes 916 with distal needles 919having injection egress ports 917. The INAS 900 also has three guidetubes 915 that include a flat wire 918 inside of the guide tube 915. Theflat wire 918 provides the shape memory and optionally the radiopacityfor visualization of the guide tubes 915. The flat wire 918 wouldtypically be made from a memory metal such as NITINOL or a springmaterial such as spring steel. The guide tubes 915 would typically bemade from a plastic material, soft enough to allow the wire 818 to causethe guide tubes 815 to form the shape shown. Also show is the sheath 912and core wire 911 which are similar in function to those shown in manyof the earlier embodiments of the INAS. It is also envisioned that theguide tubes 915 themselves would include a radiopaque material such asTungsten or Barium.

While each of the INAS embodiments shown herein have closed and openpositions where the close position has the injection needles completelyenclosed, it is envisioned that the system would function with an outersheath that is open at its distal end such as is shown in the McGuckindevice of U.S. Pat. No. 7,087,040. In such an embodiment, needlestickinjuries could be prevented by withdrawing the injection needles back inthe proximal direction a sufficient distance that they are hidden. Aninterlock in the proximal section and/or handle could lock the motion ofthe needles to prevent them from accidentally moving in the distaldirection. This concept would work with the INAS designs of FIGS. 1-10as well as those embodiments with guide tubes shown in FIGS. 11-35 wherethe needles would be retracted proximally within the guide tubes andthen the guide tubes would be retracted back into the sheath.

FIG. 36A is a longitudinal cross section view of another embodiment ofthe distal portion of an injector tube 956 with distal injection needle959 of the INAS 950. The other structure of the INAS 950 is similar tothe INAS 10 of FIG. 1 . The injection needle 959 has injection egress957. A stylette 958 is shown inside the lumen of the injector tube 956.The stylette 958 has two potential uses, 1) it can stiffen the injectortube 956 to it will maintain its proper curved shape and betterpenetrate the inside wall of the target vessel and 2) it could provideadditional radiopacity for visualization under fluoroscopy. It is alsoenvisioned that the injection needle 959 could have a non sharp end andthe stylus 958 could extend beyond the injection egress 957 and besharpened to provide means to penetrate the inside wall of the targetvessel. The stylette 958 would be removed completely or pulled back soas not to obstruct flow once the needles are properly positioned. A cordsuch as the cord 13 of the INAS 10 of FIG. 1 could provide the means tolimit penetration depth in this design.

FIG. 36B is a longitudinal cross section view of still anotherembodiment of the distal portion of a plastic proximal tube 965 of theINAS 950 with an injector tube 966 with distal injection needle 969inserted into the distal end of the injector tube 965. Radiopacity isprovided by a radiopaque marker band 962 on the injector tube 965 and aradiopaque wire 968 inside of the injector tube 966. The injectionneedle 969 has injection egress 957. The injector tube 965 would be madefrom a pre-shaped plastic such as urethane or polyamide or a combinationof two or more layers of plastic. The distal end 961 of the injectortube 965 provides the means to limit penetration of the needle 969. Itis also envisioned that the injector tube 966 can be made from aradiopaque metal such as tantalum or L605 cobalt chromium or theinjector tube 966 could be plated or coated with a radiopaque metal suchas gold. In those cases, there would not be a need for the radiopaquewire 968

FIG. 36C is a longitudinal cross section view of still anotherembodiment of the distal portion of a metal proximal tube 975 with aninjector tube 976 with distal injection needle 979 inserted into thedistal end of the injector tube 975. Radiopacity is provided by aradiopaque marker band 972 on the injector tube 975 and a radiopaquewire 978 inside of the injector tube 976. The injection needle 979 hasinjection egress 977. The injector tube 975 would be made from apre-shaped metal such as NITINOL. The distal end 971 of the injectortube 975, provides the means to limit penetration of the needle 979.

While this description has focused on use of the INAS for use inablation of tissue, it is also clearly envisioned that the apparatus andmethods of FIGS. 1-33 can be applied to the use of this apparatus toinject any fluid for any purpose including that of local drug deliveryinto a specified portion of a blood vessel or the volume of tissue justoutside of a blood vessel.

Various other modifications, adaptations, and alternative designs are ofcourse possible in light of the above teachings. Therefore, it should beunderstood at this time that within the scope of the appended claims theinvention may be practiced otherwise than as specifically describedherein.

1-72. (canceled)
 73. A method comprising: providing a system comprisinga catheter body, a first guide tube, a second guide tube, a firstinjection needle, and a second injection needle, the first injectionneedle disposed within a lumen of the first guide tube, the secondinjection needle disposed within a lumen of the second guide tube;advancing the first guide tube and the second guide tube toward a wallof a target vessel; advancing the first injection needle and the secondinjection needle through the first guide tube and the second guide tube,respectively, to penetrate an internal elastic lamina of the targetvessel; and delivering an ablative fluid through the first injectionneedle and the second injection needle to deliver an ablative fluid ator deep to an adventitial plane of the target vessel.
 74. The method ofclaim 73, wherein the ablative fluid fills a layer containingsympathetic nerves.
 75. The method of claim 73, wherein the ablativefluid flows circumferentially around the target vessel.
 76. The methodof claim 73, wherein the ablative fluid comprises ethanol.
 77. Themethod of claim 73, wherein the target vessel is a renal artery.
 78. Themethod of claim 73, wherein the first injection needle and the secondinjection needle advance a preset depth.
 79. The method of claim 73,wherein the first injection needle advances at least 0.5 mm beyond theinternal elastic lamina.
 80. The method of claim 73, wherein the firstinjection needle advances between 0.5 mm and 4 mm beyond the internalelastic lamina.
 81. The method of claim 73, wherein the first injectionneedle comprises an injection egress between 1 mm and 2 mm beyond adistal end of the first guide tube.
 82. The method of claim 73, whereinbetween 0.1 ml and 5 ml of the ablative fluid is delivered.
 83. A methodcomprising: providing a system comprising a catheter body, a first guidetube, a second guide tube, a first injection needle, and a secondinjection needle, the first injection needle disposed within a lumen ofthe first guide tube, the second injection needle disposed within alumen of the second guide tube; advancing the first guide tube and thesecond guide tube toward a wall of a target vessel; advancing the firstinjection needle and the second injection needle through the first guidetube and the second guide tube, respectively, to penetrate the wall ofthe target vessel; and delivering an ablative fluid through the firstinjection needle and the second injection needle for ablation appliedbeyond an intimal surface of the target vessel to selectively target alayer of the target vessel.
 84. The method of claim 83, wherein theablative fluid is delivered around an entire circumference of the targetvessel.
 85. The method of claim 83, wherein the ablative fluid ablatesnerves that run along an adventitial plane of the target vessel.
 86. Themethod of claim 83, wherein the ablative fluid ablates nerves in anadventitial or peri-adventitial layer of the target vessel whileminimizing intimal and medial injury.
 87. The method of claim 83,wherein the first injection needle and the second injection needle onlypenetrate into tissue to a preset distance.
 88. A method comprising:providing a system comprising a catheter body, a first guide tube, asecond guide tube, a third guide tube, a first injection needle, asecond injection needle, and a third injection needle, the firstinjection needle disposed within a lumen of the first guide tube, thesecond injection needle disposed within a lumen of the second guidetube, the third injection needle disposed within a lumen of the thirdguide tube; advancing the first guide tube, the second guide tube, andthe third guide tube toward a wall of a target vessel; advancing thefirst injection needle, the second injection needle, and the thirdinjection needle through the first guide tube, the second guide tube,and the third guide tube, respectively, to penetrate the wall of thetarget vessel; and delivering an ablative fluid through the firstinjection needle and the second injection needle for circumferentialfilling of a space outside of an adventitial layer of the target vessel.89. The method of claim 88, wherein the ablative fluid penetratescircumferentially into a ring segment of the target vessel.
 90. Themethod of claim 88, wherein the ablative fluid ablates sympathetic nervefibers of the adventitial layer.
 91. The method of claim 88, wherein adepth setting for penetration of the first injection needle, the secondinjection needle, and the third injection needle is known prior toadvancing the first injection needle, the second injection needle, andthe third injection needle.
 92. The method of claim 88, whereindelivering the ablative fluid comprises at least three points ofsimultaneous injection.